Moving grpc status and helper to grpc project

[eddynaka]

Fixes #.

Changes

Please provide a brief description of the changes here.

For significant contributions please make sure you have completed the following items:

• CHANGELOG.md updated for non-trivial changes
• Design discussion issue #
• Changes in public API reviewed

[codecov]

Codecov Report

Merging #1422 into master will increase coverage by 0.04%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #1422      +/-   ##
==========================================
+ Coverage   81.84%   81.89%   +0.04%     
==========================================
  Files         227      227              
  Lines        6086     6086              
==========================================
+ Hits         4981     4984       +3     
+ Misses       1105     1102       -3     

Impacted Files	Coverage Δ
src/OpenTelemetry.Api/Trace/SpanHelper.cs	100.00% <ø> (ø)
...try.Instrumentation.GrpcNetClient/GrpcTagHelper.cs	100.00% <100.00%> (ø)
...nTelemetry/Internal/OpenTelemetrySdkEventSource.cs	75.34% <0.00%> (+1.36%)	⬆️
...ter.ZPages/Implementation/ZPagesActivityTracker.cs	100.00% <0.00%> (+2.85%)	⬆️
...ZPages/Implementation/ZPagesExporterEventSource.cs	62.50% <0.00%> (+6.25%)	⬆️

[CodeBlanch]

LGTM

[cijothomas]

One less public API!