Expose stage services via API
What does this MR do?
Related issue: #12196 (closed)
This MR is exposing Stage API to the frontend for listing, creating, updating and deleting stages. I set the ~backstage label since the FE will be implemented in a follow up MR.
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Screenshots
The form (UI) is implemented in another MR (right side)
Does this MR meet the acceptance criteria?
Conformity
Security
Permission is enforced in the controllers and in the service classes.
Edited by Michael Kozono