chore: clean up API for release

[dyladan]

Summary

• Do not export Noop* classes
  • These were only depended on by tests in other packages. For now, I've made them import from the deep direct path like import {} from '@opentelemetry/api/build/src/folder/file'; but in the future, other package tests should probably not depend on these internal details of the API if possible.
• Do not export NOOP_* constants
• Do not export INVALID_* SpanContext constants
• Rename api.StatusCode to api.SpanStatusCode
• Move createContextKey to context.createKey
• Rename api.EntryValue to api.BaggageEntryValue
• Rename api.EntryTtl to api.BaggageEntryTtl

[codecov]

Codecov Report

Merging #1759 (9357fec) into master (7e5da41) will decrease coverage by 0.20%.
The diff coverage is 77.52%.

@@            Coverage Diff             @@
##           master    #1759      +/-   ##
==========================================
- Coverage   92.07%   91.87%   -0.21%     
==========================================
  Files         166      166              
  Lines        5593     5609      +16     
  Branches     1199     1201       +2     
==========================================
+ Hits         5150     5153       +3     
- Misses        443      456      +13     

Impacted Files	Coverage Δ
...ges/opentelemetry-instrumentation-http/src/http.ts	95.49% <0.00%> (ø)
packages/opentelemetry-metrics/src/Metric.ts	92.10% <0.00%> (ø)
packages/opentelemetry-metrics/src/export/types.ts	100.00% <ø> (ø)
packages/opentelemetry-metrics/src/types.ts	100.00% <ø> (ø)
packages/opentelemetry-plugin-http/src/http.ts	97.28% <0.00%> (ø)
...ackages/opentelemetry-shim-opentracing/src/shim.ts	87.70% <0.00%> (ø)
packages/opentelemetry-tracing/src/Span.ts	98.07% <ø> (ø)
...es/opentelemetry-core/src/trace/NoRecordingSpan.ts	31.57% <18.75%> (-68.43%)	⬇️
packages/opentelemetry-api/src/api/context.ts	84.84% <50.00%> (-2.25%)	⬇️
.../opentelemetry-exporter-collector/src/transform.ts	85.47% <66.66%> (ø)
... and 21 more

[obecny]

lgtm, don't see any blocker here

[obecny]

does it mean that NoopTracerProvider is not available or it is in different namespace ?

[dyladan]

The NoopTracer provider is not explicitly exported by the package index so the only way to get it is by its full path. This means it is not part of the API that we claim to be "stable" and could move, change name, be removed, or similar. It also means it will not show up in autocomplete and such when people try to explore the package so it will prevent some confusion.

[vmarchaud]

I'm closing since the api has been moved anyway