Adding scala profile for kafka 2.x build and remove root pom scala dependencies

[xiangfu0]

Description

Adding scala profile for kafka 2.x build and remove root pom scala dependencies

Upgrade Notes

Does this PR prevent a zero down-time upgrade? (Assume upgrade order: Controller, Broker, Server, Minion)

• Yes (Please label as backward-incompat, and complete the section below on Release Notes)

Does this PR fix a zero-downtime upgrade introduced earlier?

• Yes (Please label this as backward-incompat, and complete the section below on Release Notes)

Does this PR otherwise need attention when creating release notes? Things to consider:

• New configuration options
• Deprecation of configurations
• Signature changes to public methods/interfaces
• New plugins added or old plugins removed

• Yes (Please label this PR as release-notes and complete the section on Release Notes)

Release Notes

Documentation

[codecov-commenter]

Codecov Report

Merging #8174 (b3fd151) into master (8d867ed) will increase coverage by 0.09%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##             master    #8174      +/-   ##
============================================
+ Coverage     71.35%   71.44%   +0.09%     
- Complexity     4306     4307       +1     
============================================
  Files          1623     1623              
  Lines         84314    84314              
  Branches      12640    12640              
============================================
+ Hits          60163    60240      +77     
+ Misses        20035    19955      -80     
- Partials       4116     4119       +3     

Flag	Coverage Δ
integration1	28.94% <ø> (+0.10%)	⬆️
integration2	27.55% <ø> (ø)
unittests1	67.94% <ø> (+0.01%)	⬆️
unittests2	14.19% <ø> (+0.02%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
...gregation/function/StUnionAggregationFunction.java	73.52% <0.00%> (-2.95%)	⬇️
.../pinot/core/query/scheduler/PriorityScheduler.java	80.82% <0.00%> (-2.74%)	⬇️
.../org/apache/pinot/core/startree/StarTreeUtils.java	69.89% <0.00%> (-2.16%)	⬇️
...lix/core/realtime/PinotRealtimeSegmentManager.java	81.67% <0.00%> (-2.10%)	⬇️
.../controller/helix/core/SegmentDeletionManager.java	72.72% <0.00%> (-0.76%)	⬇️
...nMaxValueBasedSelectionOrderByCombineOperator.java	71.96% <0.00%> (-0.76%)	⬇️
...a/org/apache/pinot/core/common/DataBlockCache.java	91.42% <0.00%> (-0.72%)	⬇️
...manager/realtime/LLRealtimeSegmentDataManager.java	70.96% <0.00%> (-0.66%)	⬇️
...ntroller/helix/core/PinotHelixResourceManager.java	65.77% <0.00%> (-0.08%)	⬇️
.../helix/core/realtime/SegmentCompletionManager.java	72.00% <0.00%> (+0.20%)	⬆️
... and 15 more

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[jackjlli]

This basically means the default scala version got downgraded from 2.13 to 2.12 in the project. Could you elaborate a bit more on the reason of doing that to the description?

[xiangfu0]

The reason is I've got a lot request for scala 2.12 support, hence make this as default and allow upgrade to 2.13.

Basically this is similar to kafka 0.9 and 2.x, users can build a connector based on the scala version from their enviroment.

[xiangfu0]

For Pinot users, there is no different in terms of using scala 2.12 or 2.13 built jars.
This is mostly for users who are integrating Pinot code and libs and making their life easier.

[jackjlli]

LGTM