[cleanup] move env vars out of /api folder

[swang392]

What does this PR do?

The environment variables in v2alpha1 aren't used in the CRDS. Moved the variables defined in /api to:

• internal/controller/datadogagent/common/envvar.go if they are used in the controller and in multiple features
• a specific envvar.go file in a feature if it's used exclusively in one feature

Motivation

We don't need to have the constants in /api if they aren't relevant to the CRDs. Moving the constants closer to where they are used makes the code easier to maintain.

Additional Notes

Anything else we should know when reviewing?

Minimum Agent Versions

Are there minimum versions of the Datadog Agent and/or Cluster Agent required?

• Agent: vX.Y.Z
• Cluster Agent: vX.Y.Z

Describe your test plan

should have no effect, everything builds and runs as normal

Checklist

• PR has at least one valid label: bug, enhancement, refactoring, documentation, tooling, and/or dependencies
• PR has a milestone or the qa/skip-qa label

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 65.51724% with 40 lines in your changes missing coverage. Please review.

Project coverage is 49.49%. Comparing base (ba1f2e5) to head (bcd38f5).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
...adogagent/component/clusterchecksrunner/default.go	0.00%	14 Missing ⚠️
...nternal/controller/datadogagent/override/global.go	52.38%	10 Missing ⚠️
pkg/datadogclient/client.go	0.00%	5 Missing ⚠️
...ller/datadogagent/feature/enabledefault/feature.go	0.00%	4 Missing ⚠️
...ntroller/datadogagent/feature/dogstatsd/feature.go	0.00%	2 Missing ⚠️
...er/datadogagent/feature/eventcollection/feature.go	50.00%	2 Missing ⚠️
pkg/remoteconfig/updater.go	0.00%	2 Missing ⚠️
internal/controller/testutils/agent.go	0.00%	1 Missing ⚠️

❌ Your patch status has failed because the patch coverage (65.51%) is below the target coverage (80.00%). You can increase the patch coverage or adjust the target coverage.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1681   +/-   ##
=======================================
  Coverage   49.49%   49.49%           
=======================================
  Files         218      218           
  Lines       21244    21244           
=======================================
  Hits        10515    10515           
  Misses      10182    10182           
  Partials      547      547           

Flag	Coverage Δ
unittests	49.49% <65.51%> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
...controller/datadogagent/component/agent/default.go	79.35% <100.00%> (ø)
...ler/datadogagent/component/clusteragent/default.go	96.89% <100.00%> (ø)
...nal/controller/datadogagent/feature/apm/feature.go	65.51% <100.00%> (ø)
...al/controller/datadogagent/feature/cspm/feature.go	75.20% <100.00%> (ø)
...nal/controller/datadogagent/feature/cws/feature.go	79.55% <100.00%> (ø)
...ntroller/datadogagent/feature/ebpfcheck/feature.go	83.60% <100.00%> (ø)
...nal/controller/datadogagent/feature/gpu/feature.go	90.47% <100.00%> (ø)
...ller/datadogagent/feature/livecontainer/feature.go	89.33% <100.00%> (ø)
...roller/datadogagent/feature/liveprocess/feature.go	92.07% <100.00%> (ø)
...ller/datadogagent/feature/logcollection/feature.go	84.61% <100.00%> (ø)
... and 20 more

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[tbavelier]

Thanks again for the effort! Left 2 non blocking comments

[tbavelier]

I'd be in favor of fully removing this file now that it's empty

[tbavelier]

nit: Could possibly move DDLogLevel over to internal/controller/datadogagent/override/envvar.go as it's only used in internal/controller/datadogagent/override/ multiple times and once in internal/controller/testutils where it could be simply replaced as a string DD_LOG_LEVEL