[OTAGENT-512] Add more configs to otel agent gateway

[songy23]

What does this PR do?

Add more configs to otel agent gateway matching the implementation in helm charts: http://github.com/DataDog/helm-charts/blob/main/charts/datadog/templates/otel-agent-gateway-deployment.yaml. Namely:

1. Replicas
2. NodeSelector
3. Affinity
4. Tolerations
5. PriorityClassName
6. Env
7. EnvFrom
8. Image
9. FeatureGates

Motivation

Implement otel agent gateway in operator.

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

For QA, use examples/datadogagent/datadog-agent-with-otelagentgateway.yaml. You can tweak the parameters based on your needs. Verify the node selector, affinity, labels, replicas etc. in the otel agent gateway deployment and pods are expected.

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
• All commits are signed (see: signing commits)

[codecov-commenter]

Codecov Report

❌ Patch coverage is 28.70370% with 77 lines in your changes missing coverage. Please review.
✅ Project coverage is 38.30%. Comparing base (08c7140) to head (81e0cda).

Files with missing lines	Patch %	Lines
pkg/testutils/builder.go	0.00%	36 Missing ⚠️
...r/datadogagent/feature/otelagentgateway/feature.go	57.40%	21 Missing and 2 partials ⚠️
...datadogagent/component/otelagentgateway/default.go	0.00%	9 Missing ⚠️
...troller/datadogagent/component_otelagentgateway.go	0.00%	6 Missing ⚠️
...datadogagentinternal/component_otelagentgateway.go	0.00%	3 Missing ⚠️

❌ Your patch status has failed because the patch coverage (28.70%) 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    #2490      +/-   ##
==========================================
- Coverage   38.34%   38.30%   -0.05%     
==========================================
  Files         300      300              
  Lines       25544    25652     +108     
==========================================
+ Hits         9795     9826      +31     
- Misses      15005    15080      +75     
- Partials      744      746       +2     

Flag	Coverage Δ
unittests	38.30% <28.70%> (-0.05%)	⬇️

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

Files with missing lines	Coverage Δ
...datadogagentinternal/component_otelagentgateway.go	0.00% <0.00%> (ø)
...troller/datadogagent/component_otelagentgateway.go	38.88% <0.00%> (-4.87%)	⬇️
...datadogagent/component/otelagentgateway/default.go	0.00% <0.00%> (ø)
...r/datadogagent/feature/otelagentgateway/feature.go	80.44% <57.40%> (-9.96%)	⬇️
pkg/testutils/builder.go	0.00% <0.00%> (ø)

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[songy23]

Talked offline, will take a look at override to check if new configs are already supported