feat: add IsRemote field to SpanContext, set by propagators

[KaindlJulian]

Which problem is this PR solving?

• Closes Add IsRemote field to SpanContext, set by propagators  #450

Short description of the changes

• Add optional isRemote to SpanContext
• Set it to true when extracting a propagated SpanContext

[codecov-io]

Codecov Report

Merging #451 into master will increase coverage by 0.29%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #451      +/-   ##
==========================================
+ Coverage   94.94%   95.23%   +0.29%     
==========================================
  Files         123      125       +2     
  Lines        5815     6279     +464     
  Branches      491      516      +25     
==========================================
+ Hits         5521     5980     +459     
- Misses        294      299       +5

Impacted Files	Coverage Δ
...lemetry-core/test/context/HttpTraceContext.test.ts	100% <ø> (ø)	⬆️
...metry-core/test/context/BinaryTraceContext.test.ts	100% <ø> (ø)	⬆️
...s/opentelemetry-core/test/context/B3Format.test.ts	100% <100%> (ø)	⬆️
...telemetry-core/src/context/propagation/B3Format.ts	96% <100%> (-0.43%)	⬇️
...core/src/context/propagation/BinaryTraceContext.ts	96.72% <100%> (-0.96%)	⬇️
...y-core/src/context/propagation/HttpTraceContext.ts	100% <100%> (ø)	⬆️
...opentelemetry-core/src/platform/node/timer-util.ts	33.33% <0%> (-16.67%)	⬇️
...ges/opentelemetry-core/src/common/ConsoleLogger.ts	91.66% <0%> (-1.67%)	⬇️
...entelemetry-core/test/common/ConsoleLogger.test.ts	100% <0%> (ø)	⬆️
... and 28 more

[mayurkale22]

Thank you so much for the contribution and welcome to OpenTelemetry 👍

[mayurkale22]

Should we also use this flag (isRemote) to set span.shared when send/transform it to Zipkin's Span format? Currently, it is set to false by default.

opentelemetry-js/packages/opentelemetry-exporter-zipkin/src/types.ts

Lines 74 to 78 in b58965c

	/**
	* True if we are contributing to a span started by another tracer (ex on a
	* different host).
	*/
	shared?: boolean;

/cc @hekike

[mayurkale22]

We have to set the flag when extracing from BinaryTraceContext - used by gRPC plugin, Could you please update the PR and include that?

[draffensperger]

Could you specify the default? I assume the default is false

[KaindlJulian]

It's not set to false anywhere explicitly so it'll be undefined by default. Should I just change the comment or add a isRemote: false to all new SpanContexts?

[mayurkale22]

Should we also use this flag (isRemote) to set span.shared when send/transform it to Zipkin's Span format? Currently, it is set to false by default.

LGTM, merging now. Let's consider above stuff for separate PR/Issue.