Logging UI ECS Migration

[ruflin]

This issue is to track the migration of the Logging UI to ECS

List of fields which need to be migrated:

• Handle change that source becomes log.path and log.source.ip
• Handle changes to nginx fields: Convert Filebeat nginx.access to ECS beats#9081
• Handle changes to apache fields: Convert apache2.access to ECS - Take 2 beats#9245

[elasticmachine]

Pinging @elastic/infrastructure-ui

[alvarolobato]

@ruflin when do we need to have this implemented? 6.6?

[ruflin]

@alvarolobato This will only be needed for 7.0.

[ruflin]

Closing this in favor of #27284 as I accidentially created it twice.