[CECO-1860][DatadogGenericResource] Add monitor support

[tbavelier]

What does this PR do?

Same as #1635 but for the "refactor" part 2 #1640

Motivation

What inspired you to submit this pull request?

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

Write there any instructions and details you may have to test your PR.

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 0% with 73 lines in your changes missing coverage. Please review.

Project coverage is 48.76%. Comparing base (090df80) to head (fadc293).

Files with missing lines	Patch %	Lines
...rnal/controller/datadoggenericresource/monitors.go	0.00%	55 Missing ⚠️
pkg/datadogclient/client.go	0.00%	7 Missing ⚠️
...nternal/controller/datadoggenericresource/utils.go	0.00%	6 Missing ⚠️
...al/controller/datadoggenericresource/controller.go	0.00%	5 Missing ⚠️

Additional details and impacted files

@@                            Coverage Diff                             @@
##           tbavelier/generic_resource_re_refactor    #1641      +/-   ##
==========================================================================
- Coverage                                   48.91%   48.76%   -0.16%     
==========================================================================
  Files                                         217      218       +1     
  Lines                                       20903    20969      +66     
==========================================================================
  Hits                                        10225    10225              
- Misses                                      10138    10204      +66     
  Partials                                      540      540              

Flag	Coverage Δ
unittests	48.76% <0.00%> (-0.16%)	⬇️

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

Files with missing lines	Coverage Δ
...al/controller/datadoggenericresource/controller.go	39.25% <0.00%> (+0.28%)	⬆️
...nternal/controller/datadoggenericresource/utils.go	50.45% <0.00%> (-2.94%)	⬇️
pkg/datadogclient/client.go	0.00% <0.00%> (ø)
...rnal/controller/datadoggenericresource/monitors.go	0.00% <0.00%> (ø)

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