feat(appset): Add support for self-signed TLS / Certificates for Gitlab Scm Provider

[ishitasequeira]

Add support for self-signed TLS / Certificates for Gitlab SCM Provider by adding a new insecure flag.

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[codecov]

Codecov Report

Patch coverage: 65.51% and project coverage change: +0.02 🎉

Comparison is base (0564249) 49.73% compared to head (6db0eac) 49.75%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #14348      +/-   ##
==========================================
+ Coverage   49.73%   49.75%   +0.02%     
==========================================
  Files         261      261              
  Lines       44707    44754      +47     
==========================================
+ Hits        22234    22268      +34     
- Misses      20286    20295       +9     
- Partials     2187     2191       +4     

Impacted Files	Coverage Δ
...cationset/controllers/applicationset_controller.go	62.53% <ø> (ø)
...licationset/generators/generator_spec_processor.go	59.63% <ø> (ø)
applicationset/generators/list.go	61.11% <ø> (ø)
applicationset/generators/pull_request.go	44.72% <0.00%> (-0.28%)	⬇️
applicationset/generators/scm_provider.go	33.33% <0.00%> (-0.20%)	⬇️
.../apis/application/v1alpha1/applicationset_types.go	31.25% <ø> (ø)
applicationset/utils/utils.go	77.49% <63.33%> (-1.52%)	⬇️
applicationset/services/scm_provider/gitlab.go	74.46% <90.00%> (+1.33%)	⬆️
applicationset/generators/cluster.go	80.34% <100.00%> (ø)
applicationset/services/pull_request/gitlab.go	89.06% <100.00%> (+1.56%)	⬆️

... and 1 file with indirect coverage changes

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[crenshaw-dev]

A couple general notes:

1. should we add the same for the pull request generator?
2. should we also provide the ability for the user to configure a cert bundle on the appset controller so that users don't have to disable cert validation?

[crenshaw-dev]

Wording nitpicks mostly.

Can you add tests to show that a self-signed cert works when specified without setting insecure: true?

[crenshaw-dev]

/cherry-pick release-2.8

[gcp-cherry-pick-bot]

Cherry-pick failed with Merge error 6fb238c7d8b05e38b1ec25aaa4eb354be31d57ee into temp-cherry-pick-2a25f0-release-2.8