Simplify public operator configuration options

[tbavelier]

What does this PR do?

Adds some +doc-gen:truncate markers on fields:

• referencing CustomConfig
• global.kubelet.host
  Adds +doc-gen:exclude to global.DisableNonResourceRules

Motivation

Simplify options for the public doc page https://docs.datadoghq.com/containers/datadog_operator/config. The children fields are "complex" especially for kubelet.host while it is not frequently modified

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
• All commits are signed (see: signing commits)

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 38.80%. Comparing base (232e661) to head (945ce1c).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2706      +/-   ##
==========================================
- Coverage   38.81%   38.80%   -0.02%     
==========================================
  Files         307      307              
  Lines       26610    26618       +8     
==========================================
  Hits        10329    10329              
- Misses      15501    15509       +8     
  Partials      780      780              

Flag	Coverage Δ
unittests	38.80% <ø> (-0.02%)	⬇️

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