Refactoring AkkaStreamletContextImpl to consolidate duplicated code

[SemanticBeeng]

What changes were proposed in this pull request?

Refactoring AkkaStreamletContextImpl to consolidate duplicated code and hide the constructor in a factory (StreamletContextFactory)

See makeConsumerSettings, withGroupId so far. This is work in progress: submitted to verify it would be agreeable to accept such a change.

Why are the changes needed?

Looking to add support for committablePartitionedShardedSource as mentioned

• https://cloudflow.zulipchat.com/#narrow/stream/263236-cloudflow/topic/hybrid.20runtime/near/285558740 and
• https://cloudflow.zulipchat.com/#narrow/stream/263236-cloudflow/topic/hybrid.20runtime/near/287714133

Does this PR introduce any user-facing change?

Not yet. Yes, AkkaStreamlet users will be able to leverage committablePartitionedShardedSource.

How was this patch tested?

Doing just cleanup refactorings first, no extra testing should be required. #todo Not yet implemented but will add tests specific for streamlets running sticky to partitions.

[lightbend-cla-validator]

Hi @SemanticBeeng,

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[lightbend-cla-validator]

Hi @SemanticBeeng,

Thank you for your contribution! We really value the time you've taken to put this together.

We see that you have signed the Lightbend Contributors License Agreement before, however, the CLA has changed since you last signed it. Please review the new CLA and sign it before we proceed with reviewing this pull request:

https://www.lightbend.com/contribute/cla

[lightbend-cla-validator]

Hi @SemanticBeeng,

Thank you for your contribution! We really value the time you've taken to put this together.

We see that you have signed the Lightbend Contributors License Agreement before, however, the CLA has changed since you last signed it. Please review the new CLA and sign it before we proceed with reviewing this pull request:

https://www.lightbend.com/contribute/cla