Add BaseOtlpExporterOptions

[vishweshbankwar]

Towards #4388
Design discussion issue #

Changes

This PR introduces a new class BaseOtlpExporterOptions. Options that are common across all 3 signals are moved here.

OtlpExporterOptions will now only contain two options ExportProcessorType and BatchExportProcessorOptions.

Will add OtlpLogExporterOptions in follow up PR.

Open question:

1. Should we include ExportProcessorType and BatchExportProcessorOptions for OtlpLogExporterOptions?
   OR
   Should we update the extension methods for adding log exporter to include these? ExporterOptions should not control the pipeline #2552

e.g.

AddOtlpExporterInternal(OpenTelemetryLoggerOptions loggerOptions, 
Action<OtlpLogExporterOptions, BatchLogExportProcessorOptions> configureExporterAndBatchProcessor)`

similar to what we have on metrics

Merge requirement checklist

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

[codecov]

Codecov Report

Merging #4391 (7b2df46) into main (7958763) will increase coverage by 0.04%.
The diff coverage is 95.55%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4391      +/-   ##
==========================================
+ Coverage   84.73%   84.78%   +0.04%     
==========================================
  Files         300      301       +1     
  Lines       12010    12010              
==========================================
+ Hits        10177    10183       +6     
+ Misses       1833     1827       -6     

Impacted Files	Coverage Δ
...r.OpenTelemetryProtocol/BaseOtlpExporterOptions.cs	95.34% <95.34%> (ø)
...orter.OpenTelemetryProtocol/OtlpExporterOptions.cs	100.00% <100.00%> (+3.63%)	⬆️
...TelemetryProtocol/OtlpExporterOptionsExtensions.cs	96.80% <100.00%> (ø)

... and 6 files with indirect coverage changes