timeseries RUM-13949 Add memory timeseries serializer and session factory

[satween]

What does this PR do?

Adds MemoryEventSerializer, which converts a batch of memory DataPoints (heap + native RSS) into a RumTimeseriesMemoryEvent JSON object. Introduces TimeseriesConfiguration as the public @ExperimentalRumApi configuration class (sampling intervals, batch size, background collection flag). Completes the pipeline with RumSessionScopeTimeseriesFactory, which wires CPU and memory readers, serializers, and the TimeseriesConfiguration together to create fully configured RumSessionScopeTimeseries instances for each new session.

Motivation

Completes the two metric types and provides the factory needed to tie the pipeline to the RUM session lifecycle.

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)

[satween]

Warning

This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite.
Learn more

• timeseries RUM-13949 Add end-to-end timeseries verification tests with CSV fixtures #3436
• timeseries RUM-13949 Wire timeseries collection into RUM session lifecycle #3435
• timeseries RUM-13949 Add memory timeseries serializer and session factory #3434 👈 (View in Graphite)
• timeseries RUM-13949: Add CPU timeseries data-point reader and serializer #3433
• timeseries RUM-13949: Implement timeseries pipeline infrastructure #3432
• timeseries RUM-13949: Add timeseries JSON schemas and regenerate API surface #3431
• feature/timeseries

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[codecov-commenter]

Codecov Report

❌ Patch coverage is 95.38462% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 72.22%. Comparing base (75b5891) to head (4c08c9b).

Files with missing lines	Patch %	Lines
...nal/timeseries/serializer/MemoryEventSerializer.kt	96.30%	0 Missing and 2 partials ⚠️
.../android/rum/timeseries/TimeseriesConfiguration.kt	90.91%	1 Missing ⚠️

Additional details and impacted files

@@                                 Coverage Diff                                  @@
##           tvaleev/feature/RUM-13949/timeseries-cpu-support    #3434      +/-   ##
====================================================================================
+ Coverage                                             72.11%   72.22%   +0.11%     
====================================================================================
  Files                                                   971      973       +2     
  Lines                                                 35588    35653      +65     
  Branches                                               5920     5929       +9     
====================================================================================
+ Hits                                                  25664    25749      +85     
+ Misses                                                 8286     8280       -6     
+ Partials                                               1638     1624      -14     

Files with missing lines	Coverage Δ
.../android/rum/timeseries/TimeseriesConfiguration.kt	90.91% <90.91%> (ø)
...nal/timeseries/serializer/MemoryEventSerializer.kt	96.30% <96.30%> (ø)

... and 38 files with indirect coverage changes

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