Add a way to create a short controller name (a:b:c) from a fully qualify one (controller::action)

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #5865
| License       | MIT
| Doc PR        | n/a

Working implementation of #5865