SHOW TOPICS should have option to hide internal topics

[rmoff]

It would be very useful if there was an option (either CLI property or syntax as part of the command) to exclude internal topics from the output of SHOW TOPICS [EXTENDED]. With something like Confluent Control Center running there's dozen of topics pre-created which creates a lot of noise for developers trying to look at the 'real' topics on the cluster. There will be instances where they will want to see them all hence this should be configurable (maybe SHOW TOPICS vs SHOW ALL TOPICS ??)

I would suggest a leading _ be the denoter for an internal topic, in the absence of any other metadata for the time being.

ksql> SHOW TOPICS EXTENDED;

 Kafka Topic                                                                                   | Partitions | Partition Replicas | Consumers | ConsumerGroups
---------------------------------------------------------------------------------------------------------------------------------------------
 _confluent-command                                                                            | 1          | 1                  | 1         | 1
 _confluent-controlcenter-5-4-0-1-actual-group-consumption-rekey                               | 1          | 1                  | 1         | 1
 _confluent-controlcenter-5-4-0-1-aggregate-topic-partition-store-changelog                    | 1          | 1                  | 0         | 0
 _confluent-controlcenter-5-4-0-1-aggregatedTopicPartitionTableWindows-ONE_MINUTE-changelog    | 1          | 1                  | 0         | 0
 _confluent-controlcenter-5-4-0-1-aggregatedTopicPartitionTableWindows-ONE_MINUTE-repartition  | 1          | 1                  | 1         | 1
 _confluent-controlcenter-5-4-0-1-aggregatedTopicPartitionTableWindows-THREE_HOURS-changelog   | 1          | 1                  | 0         | 0
 _confluent-controlcenter-5-4-0-1-aggregatedTopicPartitionTableWindows-THREE_HOURS-repartition | 1          | 1                  | 1         | 1
 _confluent-controlcenter-5-4-0-1-AlertHistoryStore-changelog                                  | 1          | 1                  | 0         | 0
 _confluent-controlcenter-5-4-0-1-cluster-rekey                                                | 1          | 1                  | 0         | 0
 _confluent-controlcenter-5-4-0-1-expected-group-consumption-rekey                             | 1          | 1                  | 1         | 1
 _confluent-controlcenter-5-4-0-1-group-aggregate-store-ONE_MINUTE-changelog                   | 1          | 1                  | 0         | 0
 _confluent-controlcenter-5-4-0-1-group-aggregate-store-THREE_HOURS-changelog                  | 1          | 1                  | 0         | 0
 _confluent-controlcenter-5-4-0-1-Group-ONE_MINUTE-changelog                                   | 1          | 1                  | 0         | 0
 _confluent-controlcenter-5-4-0-1-group-stream-extension-rekey                                 | 1          | 1                  | 1         | 1
 _confluent-controlcenter-5-4-0-1-Group-THREE_HOURS-changelog                                  | 1          | 1                  | 0         | 0
 _confluent-controlcenter-5-4-0-1-KSTREAM-OUTEROTHER-0000000105-store-changelog                | 1          | 1                  | 0         | 0
 _confluent-controlcenter-5-4-0-1-KSTREAM-OUTERTHIS-0000000104-store-changelog                 | 1          | 1                  | 0         | 0
 _confluent-controlcenter-5-4-0-1-metrics-trigger-measurement-rekey                            | 1          | 1                  | 1         | 1
 _confluent-controlcenter-5-4-0-1-MetricsAggregateStore-changelog                              | 1          | 1                  | 0         | 0
 _confluent-controlcenter-5-4-0-1-MetricsAggregateStore-repartition                            | 1          | 1                  | 1         | 1
 _confluent-controlcenter-5-4-0-1-monitoring-aggregate-rekey-store-changelog                   | 1          | 1                  | 0         | 0
 _confluent-controlcenter-5-4-0-1-monitoring-message-rekey-store                               | 1          | 1                  | 1         | 1
 _confluent-controlcenter-5-4-0-1-monitoring-trigger-event-rekey                               | 1          | 1                  | 1         | 1
 _confluent-controlcenter-5-4-0-1-MonitoringMessageAggregatorWindows-ONE_MINUTE-changelog      | 1          | 1                  | 0         | 0
 _confluent-controlcenter-5-4-0-1-MonitoringMessageAggregatorWindows-ONE_MINUTE-repartition    | 1          | 1                  | 1         | 1
 _confluent-controlcenter-5-4-0-1-MonitoringMessageAggregatorWindows-THREE_HOURS-changelog     | 1          | 1                  | 0         | 0
 _confluent-controlcenter-5-4-0-1-MonitoringMessageAggregatorWindows-THREE_HOURS-repartition   | 1          | 1                  | 1         | 1
 _confluent-controlcenter-5-4-0-1-MonitoringStream-ONE_MINUTE-changelog                        | 1          | 1                  | 0         | 0
 _confluent-controlcenter-5-4-0-1-MonitoringStream-ONE_MINUTE-repartition                      | 1          | 1                  | 1         | 1
 _confluent-controlcenter-5-4-0-1-MonitoringStream-THREE_HOURS-changelog                       | 1          | 1                  | 0         | 0
 _confluent-controlcenter-5-4-0-1-MonitoringStream-THREE_HOURS-repartition                     | 1          | 1                  | 1         | 1
 _confluent-controlcenter-5-4-0-1-MonitoringTriggerStore-changelog                             | 1          | 1                  | 0         | 0
 _confluent-controlcenter-5-4-0-1-MonitoringVerifierStore-changelog                            | 1          | 1                  | 0         | 0
 _confluent-controlcenter-5-4-0-1-TriggerActionsStore-changelog                                | 1          | 1                  | 0         | 0
 _confluent-controlcenter-5-4-0-1-TriggerEventsStore-changelog                                 | 1          | 1                  | 0         | 0
 _confluent-metrics                                                                            | 12         | 1                  | 12        | 1
 _confluent-monitoring                                                                         | 1          | 1                  | 1         | 1
 _kafka-connect-configs                                                                        | 1          | 1                  | 0         | 0
 _kafka-connect-offsets                                                                        | 25         | 1                  | 0         | 0
 _kafka-connect-status                                                                         | 5          | 1                  | 0         | 0
 _schemas                                                                                      | 1          | 1                  | 0         | 0
 jdbc_CUSTOMERS                                                                                | 1          | 1                  | 0         | 0
 ratings                                                                                       | 1          | 1                  | 0         | 0
---------------------------------------------------------------------------------------------------------------------------------------------

[spena]

This was implemented in Feb/2020 #4322.
It uses the SHOW [ALL] TOPICS [EXTENDED] syntax.