Some informer optimizations

[mariomac]

Removes some messages that were flooding debug log.

Prevents forwarding headless services to the client.

Slightly optimizes the informers' storage.

[codecov]

Codecov Report

Attention: Patch coverage is 80.00000% with 6 lines in your changes missing coverage. Please review.

Project coverage is 80.96%. Comparing base (3a57830) to head (8d52cd9).
Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
pkg/kubecache/meta/informers.go	25.00%	2 Missing and 1 partial ⚠️
pkg/kubecache/meta/informers_init.go	88.00%	2 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1360      +/-   ##
==========================================
+ Coverage   72.13%   80.96%   +8.83%     
==========================================
  Files         144      145       +1     
  Lines       14661    14665       +4     
==========================================
+ Hits        10575    11873    +1298     
+ Misses       3390     2216    -1174     
+ Partials      696      576     -120     

Flag	Coverage Δ
integration-test	59.04% <0.00%> (+0.11%)	⬆️
k8s-integration-test	59.72% <70.00%> (+0.06%)	⬆️
oats-test	34.31% <0.00%> (+0.01%)	⬆️
unittests	52.25% <70.00%> (?)

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