RUM-2014 Add the synchronous equivalent of readNextBatch and confirmBatchRead in Storage API

[mariusc83]

In this PR we are replacing the async methods readNextBatch and confirmBatchRead from Storage interface with their synchronous equivalents.

What does this PR do?

A brief description of the change being made with this pull request.

Motivation

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Additional Notes

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Review checklist (to be filled by reviewers)

• Feature or bugfix MUST have appropriate tests (unit, integration, e2e)
• Make sure you discussed the feature or bugfix with the maintaining team in an Issue
• Make sure each commit and the PR mention the Issue number (cf the CONTRIBUTING doc)

[xgouchet]

Warning

We still have asynchronous confirmBatchRead in the DataUploader, so we might want to also have a synchronous method there WDYT?

[mariusc83]

Warning

We still have asynchronous confirmBatchRead in the DataUploader, so we might want to also have a synchronous method there WDYT?

I actually wanted to do that but then @0xnm said that it might still have sense to call that method only with a callback.
@0xnm what do you think ?

[codecov-commenter]

Codecov Report

Merging #1768 (c699fc4) into develop (2716cb6) will increase coverage by 0.12%.
The diff coverage is 90.91%.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #1768      +/-   ##
===========================================
+ Coverage    83.42%   83.55%   +0.12%     
===========================================
  Files          469      469              
  Lines        16434    16431       -3     
  Branches      2454     2465      +11     
===========================================
+ Hits         13710    13728      +18     
+ Misses        2053     2030      -23     
- Partials       671      673       +2     

Files	Coverage Δ
.../android/core/internal/data/upload/UploadWorker.kt	86.49% <100.00%> (-0.36%)	⬇️
...core/internal/data/upload/v2/DataUploadRunnable.kt	96.77% <100.00%> (-0.37%)	⬇️
...droid/core/internal/persistence/AbstractStorage.kt	100.00% <100.00%> (ø)
...d/core/internal/persistence/ConsentAwareStorage.kt	98.70% <100.00%> (-0.08%)	⬇️
...dog/android/core/internal/persistence/BatchData.kt	72.22% <72.22%> (ø)

... and 22 files with indirect coverage changes

[0xnm]

lgtm! need also to delete duplicate DataUploader, DataFlusher, etc. files.