Fix inconsistencies in the readme, add Gateway API HTTPRoute support

[nerothank]

The current version of the helm chart provided by An Otter Wiki works well and provides most functionality that most users would require. For my specific use-case there are some things missing, that I would like to contribute. Apart from new functionality there are also some changes to the README that fix inconsistencies and missing information.

Proposed changes

New functionality

• Add support for GatewayAPI HTTPRoute configuration
• Add value to optionally configure labels to be added to pods
• Adds documentation for the new functionality in the README

Fixes to the README

• Mention the option of using persistence.existingClaim that was undocumented before, and add missing value table entry
• Add missing values table entries for:
  • ingress.annotations
  • persistence.annotations
  • persistence.subPath

Common

• Update the helm chart version to 0.2.0 due to the new functionality introduced.

Tests

The chart has been successfully tested:

• using only "old" values, assuring the update does not break current installations
• with the new values incorporated, ensuring the new functionality actually works
• with the new default values provided with the chart

[redimp]

Hey @nerothank,

Thanks for the Helm chart improvements! These are genuinely useful additions and
cleanups. Nice work on:

• Gateway API HTTPRoute support as a first-class alternative to Ingress,
  including the NOTES.txt output for it
• persistence.existingClaim so users can bring their own PVC (plus the requirements note that PV provisioning isn't mandatory)
• ingress.annotations / httproute.annotations / persistence.annotations and podLabelsAdditional for customizing generated resources
• The values.yaml regrouping into logical sections and the README table now documenting the previously-missing options

I did find three template bugs that block rendering (I know the PR is still a draft/untested, flagging them so they're captured). I've left inline comments with suggested fixes on each.

Please review and fix what I've found. Make sure helm lint works. Looking
forward to merge this.

[nerothank]

Hi @redimp

Thank you for your valuable insights. I fixed the issues you mentioned and performed first tests on my k3s cluster.
It seems to work well so far. As it is getting late here and I have not tested to the extend I would like, I will still leave this on draft for now.

I should be able to test in more detail this weekend.