Stabilize RetryPolicy API for OTLP exporters

[jack-berg]

We discussed the stability status of OTLP exporter retry in the 5/25 java SIG. I mentioned that while I still don't think we can enable retry by default in autoconfigure until this spec issue is resolved, I do think we should stabilize the API configuration of retry.

This means moving RetryPolicy, RetryPolicyBuilder to stable package / artifact, and adding setRetryPolicy(RetryPolicy) methods to the OTLP exporter builder classes. That's what this PR accomplishs.

There's an interesting question about where RetryPolicy should live. It currently lives in an internal package in opentelemetry-exporters-common, which has no public API surface area. Rather than adding new public API surface area and being stuck with that artfiact / package, I thought a better home would be opentelemetry-sdk-common.

[codecov]

Codecov Report

Patch coverage: 100.00% and project coverage change: -0.01 ⚠️

Comparison is base (b5b02eb) 91.33% compared to head (f8dd309) 91.32%.

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #5524      +/-   ##
============================================
- Coverage     91.33%   91.32%   -0.01%     
+ Complexity     4969     4954      -15     
============================================
  Files           552      551       -1     
  Lines         14591    14588       -3     
  Branches       1357     1357              
============================================
- Hits          13326    13323       -3     
  Misses          876      876              
  Partials        389      389              

Impacted Files	Coverage Δ
...ry/exporter/internal/grpc/GrpcExporterBuilder.java	98.71% <ø> (ø)
...try/exporter/internal/grpc/ManagedChannelUtil.java	85.71% <ø> (ø)
...ry/exporter/internal/http/HttpExporterBuilder.java	92.15% <ø> (ø)
...etry/exporter/internal/retry/RetryInterceptor.java	100.00% <ø> (ø)
...entelemetry/exporter/internal/retry/RetryUtil.java	100.00% <ø> (ø)
...lemetry/exporter/otlp/internal/OtlpConfigUtil.java	87.59% <ø> (ø)
...orter/sender/okhttp/internal/OkHttpHttpSender.java	98.43% <ø> (ø)
...nder/okhttp/internal/OkHttpHttpSenderProvider.java	100.00% <ø> (ø)
...lp/http/logs/OtlpHttpLogRecordExporterBuilder.java	90.90% <100.00%> (+0.90%)	⬆️
...lp/http/metrics/OtlpHttpMetricExporterBuilder.java	95.55% <100.00%> (+0.31%)	⬆️
... and 8 more

... and 2 files with indirect coverage changes

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