Otlp exporter options

[Austin-Tan]

Fixes #1494 .

Following closely the recent PRs #1584 and #1504 , just applying also to the Otlp Exporter.

Will update the ReadMes for the new BatchExporterOptions for all three exporters in a separate PR.

Changes

• CHANGELOG.md updated for non-trivial changes
• Design discussion issue #
• Changes in public API reviewed

[codecov]

Codecov Report

Merging #1587 (d7798c7) into master (b710c31) will decrease coverage by 0.09%.
The diff coverage is 55.00%.

@@            Coverage Diff             @@
##           master    #1587      +/-   ##
==========================================
- Coverage   80.74%   80.64%   -0.10%     
==========================================
  Files         242      242              
  Lines        6544     6562      +18     
==========================================
+ Hits         5284     5292       +8     
- Misses       1260     1270      +10     

Impacted Files	Coverage Δ
....Exporter.Jaeger/JaegerExporterHelperExtensions.cs	15.38% <0.00%> (-17.95%)	⬇️
...nTelemetryProtocol/OtlpExporterHelperExtensions.cs	92.30% <87.50%> (-7.70%)	⬇️
...Telemetry.Exporter.Jaeger/JaegerExporterOptions.cs	100.00% <100.00%> (ø)
...orter.OpenTelemetryProtocol/OtlpExporterOptions.cs	100.00% <100.00%> (ø)
...ZPages/Implementation/ZPagesExporterEventSource.cs	56.25% <0.00%> (-6.25%)	⬇️
...ter.ZPages/Implementation/ZPagesActivityTracker.cs	97.14% <0.00%> (-2.86%)	⬇️