[Issue-494] FLIP-107: Expose metadata for the new table source

[thekingofcity]

Change log description

FLIP-107 has added the support for metadata along with the event for both table source and sink.

For table source, we export the EventPointer in the table source. By doing this, we can cover the benifit similar with #180 for DataStream Source.

Purpose of the change

Fixes #494

What the code does

• Use the new FlinkPravegaDynamicDeserializationSchema that expose the metadata from the EventRead. For now, only EventPointer is supported as the other two (scope adn stream) is not exposed from Pravega.
• Implement the SupportsReadingMetadata for FlinkPravegaDynamicTableSource.
• Test the corresponding code.

How to verify it

./gradlew clean build passes.

[codecov]

Codecov Report

Merging #504 (75fa7b9) into master (35c5358) will increase coverage by 0.48%.
The diff coverage is 93.33%.

@@             Coverage Diff              @@
##             master     #504      +/-   ##
============================================
+ Coverage     82.48%   82.97%   +0.48%     
- Complexity      487      498      +11     
============================================
  Files            44       45       +1     
  Lines          2284     2326      +42     
  Branches        224      231       +7     
============================================
+ Hits           1884     1930      +46     
+ Misses          236      230       -6     
- Partials        164      166       +2     

Impacted Files	Coverage Δ	Complexity Δ
...avega/connectors/flink/util/FlinkPravegaUtils.java	72.09% <ø> (ø)	7.00 <0.00> (ø)
.../dynamic/table/FlinkPravegaDynamicTableSource.java	71.95% <92.85%> (+8.79%)	11.00 <9.00> (+4.00)
...able/FlinkPravegaDynamicDeserializationSchema.java	94.11% <94.11%> (ø)	5.00 <5.00> (?)
...nk/dynamic/table/FlinkPravegaDynamicTableSink.java	63.82% <0.00%> (+2.12%)	5.00% <0.00%> (+1.00%)
...nk/serialization/PravegaDeserializationSchema.java	84.61% <0.00%> (+23.07%)	8.00% <0.00%> (+1.00%)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 35c5358...75fa7b9. Read the comment docs.

[crazyzhou]

LGTM.