[part 7] refactor!(telemetry): improve telemetry lifecycle

[dmehala]

Description

Now, telemetry module follows RAII. The app-started event is emitted only at the construction of the module while the app-closing event is emitted at the destruction of the module. This enforce the telemetry specs.

Changes:

• add support for install_signature.
• add support for product in configuration that will be reported in app-started message.
• unit tests

For reference:

• Part 1: [part 1] refactor!: expose telemetry module #166
• Part 2: [part 2] refactor!(telemetry): move telemetry logic from DatadogAgent #194
• Part 3: [part 3] refactor!(telemetry): introduce a singleton #195
• Part 4: [part 4] fix(telemetry): report logs #199
• Part 5: [part 5] refactor!(telemetry): use configured intervals #203
• Part 6: [part 6] refactor!(telemetry): remove dependency on TracerTelemetry #204

[pr-commenter]

Benchmarks

Benchmark execution time: 2025-04-10 12:13:26

Comparing candidate commit 2a257ea in PR branch dmehala/telemetry/part-7-lifecycle with baseline commit c85660b in branch main.

Found 0 performance improvements and 0 performance regressions! Performance is the same for 1 metrics, 0 unstable metrics.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 64.89362% with 33 lines in your changes missing coverage. Please review.

Project coverage is 89.67%. Comparing base (c85660b) to head (2a257ea).

Files with missing lines	Patch %	Lines
src/datadog/telemetry/telemetry_impl.cpp	73.43%	17 Missing ⚠️
include/datadog/telemetry/product.h	0.00%	15 Missing ⚠️
src/datadog/tracer_config.cpp	83.33%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #205      +/-   ##
==========================================
- Coverage   90.21%   89.67%   -0.55%     
==========================================
  Files          79       80       +1     
  Lines        4672     4705      +33     
==========================================
+ Hits         4215     4219       +4     
- Misses        457      486      +29     

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