[Trace SDK] Send resource once to processor and exporter, and not with every span

[lalitb]

Fixes #1124

Changes

The changes were done earlier for Logs SDK in #1636 . Creating similar PR for Trace SDK.

Stress test: (~ 12% improvement)
before:

Number of threads: 16
Throughput: 9,432,600 iterations/sec
Throughput: 9,403,800 iterations/sec

after:

Number of threads: 16
Throughput: 11,028,400 iterations/sec
Throughput: 11,029,800 iterations/sec

Benchmarks: (~10% improvement):
start-end-span/always-sample:
before: 297.20, after: 269.55

Merge requirement checklist

• CONTRIBUTING guidelines followed
• Unit tests added/updated (if applicable)
• Appropriate CHANGELOG.md files updated for non-trivial, user-facing changes
• Changes in public API reviewed (if applicable)

[codecov]

Codecov Report

Attention: Patch coverage is 58.22785% with 33 lines in your changes are missing coverage. Please review.

Project coverage is 74.4%. Comparing base (7cad751) to head (a39b460).
Report is 1 commits behind head on main.

❗ Current head a39b460 differs from pull request most recent head fa1e527

Please upload reports for the commit fa1e527 to get more accurate results.

Files	Patch %	Lines
opentelemetry-stdout/src/trace/exporter.rs	0.0%	11 Missing ⚠️
opentelemetry-otlp/src/exporter/http/mod.rs	0.0%	10 Missing ⚠️
opentelemetry-stdout/src/trace/transform.rs	0.0%	7 Missing ⚠️
opentelemetry-otlp/src/exporter/http/trace.rs	0.0%	4 Missing ⚠️
opentelemetry-sdk/src/trace/span_processor.rs	93.3%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##            main   #1830     +/-   ##
=======================================
- Coverage   74.4%   74.4%   -0.1%     
=======================================
  Files        122     122             
  Lines      19767   19807     +40     
=======================================
+ Hits       14723   14750     +27     
- Misses      5044    5057     +13     

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[TommyCpp]

Looks good. Thanks