Remove Jackson dependency from exporters

[brunobat]

Partially fixes #8533

This was implemented as a PoC to evaluate the complexity of removing Jackson and do in house JSON serialization/deserialization to avoid the complexity of: #8544

It turns out that this has a lot more added code, but it's related with tests.
Serious review needs to be placed into StreamingJsonWriter and StringJsonWriter.

This shouldn't be the last location of the JSON classes. They need to be placed on a SDK common lib to allow consumption by Declarative Config.

Assisted-By: Claude Opus 4.6 noreply@anthropic.com

[codecov]

Codecov Report

❌ Patch coverage is 88.58025% with 37 lines in your changes missing coverage. Please review.
✅ Project coverage is 90.95%. Comparing base (77eb68d) to head (57b8227).
⚠️ Report is 10 commits behind head on main.

Files with missing lines	Patch %	Lines
...exporter/internal/marshal/StreamingJsonWriter.java	81.81%	12 Missing and 6 partials ⚠️
...emetry/exporter/internal/marshal/JsonEscaping.java	87.17%	7 Missing and 3 partials ⚠️
...ry/exporter/internal/marshal/StringJsonWriter.java	90.90%	5 Missing and 1 partial ⚠️
...etry/exporter/internal/marshal/JsonSerializer.java	94.00%	3 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #8546      +/-   ##
============================================
+ Coverage     90.94%   90.95%   +0.01%     
- Complexity    10210    10284      +74     
============================================
  Files          1013     1016       +3     
  Lines         27175    27411     +236     
  Branches       3184     3203      +19     
============================================
+ Hits          24714    24932     +218     
- Misses         1734     1746      +12     
- Partials        727      733       +6     

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