Trigger Schema Generated Tool

[SpiritZhou]

Generating trigger metadata schema according to new declarative scaler configuration, which can be used for validation or other related improvement.

Input:
make generate-scaler-schemas [--keda-version][--scalers-builder-file][--scalers-files-dir][--specify-scaler][--output-file-path]

Output:
scaler-metadata-schemas.yaml

Checklist

• When introducing a new scaler, I agree with the scaling governance policy
• I have verified that my change is according to the deprecations & breaking changes policy
• Tests have been added
• Changelog has been updated and is aligned with our changelog requirements
• A PR is opened to update our Helm chart (repo) (if applicable, ie. when deployment manifests are modified)
• A PR is opened to update the documentation on (repo) (if applicable)
• Commits are signed with Developer Certificate of Origin (DCO - learn more)

Relates to # #6345

[JorTurFer]

This PR is simply awesome! Could I suggest generating the output also as json as add a verification step during the CI to verify that the generated schemas are up to date?

[JorTurFer]

This PR is simply awesome! Could I suggest generating the output also as json as add a verification step during the CI to verify that the generated schemas are up-to-date?

And probably we want to pull the schema during the release too, using the specific version of the release

[SpiritZhou]

Sure, will add json as one more output file formate.

[zroubalik]

Great stuff!

Minor improvements/suggestions:

1. change the ouptup filename from scaler-metadata-schemas to scalers-metadata-schema
2. store the schema in schema/generated
3. regenerate the schema as part of the other generation stuff (probalby build step in the Makefile)
4. add a verification step to make sure schema is up to data (similar like it is done for clientset)
5. let's produce versioned schema file in the release pipeline named scalers-metadata-schema-v$KEDA_VERSION.json/yaml