Add support for Azure App Service cloud metadata

[axw]

Extend the Azure cloud metadata provider to check for App Service environment variables, and implement the Gherkin spec.

Closes #863

[ghost]

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Build stats

• Build Cause: Pull request #914 updated

• Start Time: 2021-03-15T02:53:11.845+0000

• Duration: 33 min 11 sec

• Commit: 5340e7c

Test stats 🧪

Test	Results
Failed	0
Passed	9953
Skipped	266
Total	10219

Trends 🧪

[codecov-io]

Codecov Report

Merging #914 (5340e7c) into master (a83b7ed) will decrease coverage by 0.11%.
The diff coverage is 62.50%.

@@            Coverage Diff             @@
##           master     #914      +/-   ##
==========================================
- Coverage   83.93%   83.82%   -0.12%     
==========================================
  Files         140      140              
  Lines        7864     7895      +31     
==========================================
+ Hits         6601     6618      +17     
- Misses        867      876       +9     
- Partials      396      401       +5     

Impacted Files	Coverage Δ
internal/apmcloudutil/azure.go	70.49% <60.00%> (-10.16%)	⬇️
apmtest/env.go	100.00% <100.00%> (ø)
profiling.go	71.92% <0.00%> (-7.02%)	⬇️
tracer.go	88.58% <0.00%> (+0.30%)	⬆️

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[stuartnelson3]

Approving as everything looks fine, but with the caveat that I'm not familiar with the codebase :)

[axw]

Approving as everything looks fine, but with the caveat that I'm not familiar with the codebase :)

@stuartnelson3 I'll walk you through this codebase sometime soonish. Thanks for the review!