make rest controller more generic to support additional workflows

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | yes
| Tests pass?   | yes
| Fixed tickets | #116
| License       | MIT
| Doc PR        | TODO

/cc @uwej711 
does it make sense to keep such a BC method? they won't be called by the provided routes anymore so maybe not having them is actually better to make the user notice there was a BC break.