Add keda-crd helm chart

[ecerulm]

Provide a description of what has been changed

Checklist

• I have verified that my change is according to the deprecations & breaking changes policy
• Commits are signed with Developer Certificate of Origin (DCO - learn more)
• README is updated with new configuration values (if applicable) learn more
• A PR is opened to update KEDA core (repo) (if applicable, ie. when deployment manifests are modified)

Fixes kedacore/keda#5575

[JorTurFer]

WDYT @tomkerkhove @zroubalik ? Maybe we can split the CRDs into a new fully isolated chart and deploy that chart as dependency of KEDA (managed by a flag). This could allow installing the CRDs in advantage, without losing the helm support for the chart.
This PR adds a symlink, but maybe we could iterate this

[tomkerkhove]

As per #226, dependency does not work properly

[JorTurFer]

No no, I meant the CRDs chart as KEDA chart dependecy, not KEDA as user dependency

[tomkerkhove]

I know, but I believe the problem will be the same - There is no guarantee that CRDs are created first nor that they will be updated (biggest issue)

[sofuture]

This would be quite nice to have, what's between here and ?

[pragmaticivan]

Worth mentioning that Karpenter moved away from Symlinks due to some conflict on updates across major versions.

aws/karpenter-provider-aws@a69a377

(Mention since this came from an issue referring to Karpenter)

[JorTurFer]

I still think that splitting the charts could be quite easy and solves the issues from other people, WDYT @wozniakjan @zroubalik ?

[zroubalik]

Maybe include this into a bigger effort with #20