feat: add endpoint with values-schema

[dennisvankekem]

Checklist

• [ ] Architecture Design Records have been added as adr/*.md and appended to list in adr/_index.md, if applicable.
• [ ] The values-schema.yaml file and test/** fixtures have been updated to reflect code changes, if applicable.
• [ ] The OpenApi Schema from redkubes/otomi-api project is compatible with definitions from values-schema.yaml file, if applicable.
• [ ] Helm releases are meeting otomi's baseline security policies, if applicable.
• [ ] Helm chart and helmfile changes are tested against upgrade scenario, if applicable.