Remove registry compatibility section

What does this MR do?

The v1 compatibility feature is not supported since registry v3.0.0.

Remove its configuration from the ConfigMap and its flags from the values file.

Closes: #2523 (closed)

Changelog: removed

Related issues

Closes: #2523 (closed)

Test plan

helm template . \
  --set certmanager-issuer.email=test@example.com \
  --set registry.compatibility.schema1.enabled=true \
  --show-only charts/registry/templates/configmap.yaml

Does not render the compatibility section anymore.

Checklist

See Definition of done.

For anything in this list which will not be completed, please provide a reason in the MR discussion.

Required

• Merge Request Title and Description are up to date, accurate, and descriptive
• MR targeting the appropriate branch
• MR has a green pipeline on GitLab.com
• When ready for review, MR is labeled "~workflow::ready for review" per the Distribution MR workflow

Expected (please provide an explanation if not completing)

• Test plan indicating conditions for success has been posted and passes
• Documentation created/updated section removed
• Tests added
• Integration tests added to GitLab QA
• Equivalent MR/issue for omnibus-gitlab opened
• Validate potential values for new configuration settings. Formats such as integer 10, duration 10s, URI scheme://user:passwd@host:port may require quotation or other special handling when rendered in a template and written to a configuration file.