chore: update API docs

[mayurkale22]

Which problem is this PR solving?

• Add missing JSDoc comments.

• Add known default values.

[codecov-io]

Codecov Report

Merging #459 into master will increase coverage by 0.23%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #459      +/-   ##
==========================================
+ Coverage      95%   95.23%   +0.23%     
==========================================
  Files         125      125              
  Lines        5981     6277     +296     
  Branches      497      516      +19     
==========================================
+ Hits         5682     5978     +296     
  Misses        299      299

Impacted Files	Coverage Δ
...opentelemetry-core/src/platform/node/timer-util.ts	33.33% <0%> (-16.67%)	⬇️
...ges/opentelemetry-core/src/common/ConsoleLogger.ts	91.66% <0%> (-3.08%)	⬇️
.../opentelemetry-core/test/metrics/NoopMeter.test.ts	94.87% <0%> (-2.19%)	⬇️
...entelemetry-core/test/common/ConsoleLogger.test.ts	100% <0%> (ø)	⬆️
...ges/opentelemetry-exporter-zipkin/src/transform.ts	100% <0%> (ø)	⬆️
...core/src/context/propagation/NoopHttpTextFormat.ts	100% <0%> (ø)	⬆️
...telemetry-plugin-grpc/test/utils/assertionUtils.ts	100% <0%> (ø)	⬆️
...ges/opentelemetry-core/test/trace/NoopSpan.test.ts	100% <0%> (ø)	⬆️
...entelemetry-exporter-jaeger/test/transform.test.ts	100% <0%> (ø)	⬆️
.../opentelemetry-exporter-zipkin/test/zipkin.test.ts	100% <0%> (ø)	⬆️
... and 21 more