Optimise path validation

[haywoodsh]

Proposed changes

Optimize path validation and add test cases.

Checklist

Before creating a PR, run through this checklist and mark each as complete.

• I have read the CONTRIBUTING doc
• I have added tests that prove my fix is effective or that my feature works
• I have checked that all unit tests pass after adding my changes
• I have updated necessary documentation
• I have rebased my branch onto main
• I will ensure my PR is targeting the main branch and pulling from my branch from my own fork

[codecov-commenter]

Codecov Report

Merging #3094 (f661486) into main (c9ea1e5) will increase coverage by 0.10%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main    #3094      +/-   ##
==========================================
+ Coverage   52.41%   52.52%   +0.10%     
==========================================
  Files          58       58              
  Lines       15997    16033      +36     
==========================================
+ Hits         8385     8421      +36     
  Misses       7336     7336              
  Partials      276      276              

Impacted Files	Coverage Δ
internal/k8s/validation.go	93.81% <100.00%> (+0.49%)	⬆️

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[shaun-nx]

Great work! 👍

[jjngx]

Great stuff 👍🏻

[ciarams87]

🚀

[luanmm]

Why consider paths like "/root", "/etc/nginx/secrets", etc... as invalids? This makes this ingress unusable in a project that has a "/root" path on it (that can't change the name, because it is a big project running for several years).

I was using normally before this PR and now can't update the cluster just because of this strange validation. If a path passes the official RFC, it should be valid. My scenario have a "/root" that has nothing to do with Linux "/root" folder (if that is the intention of the validation).

Other validations seems useful, but this one is just nonsense (with all the respect).