[FEATURE]: Add search for empty folders using FDUPES tooling

[jfandy1982]

Is your feature request related to a problem? Please describe.
On the NAS server, we currently perform a clean up after identifying file duplicates manually. During that clean up, it might happen, that also empty folders are kept.
Also previous attempts in the past might have left a few empty folders.
That makes the list of folders quite large avoiding, that the manual clean up really happens.

Describe the solution you'd like
Beside the identification of duplicates, it would make sense to get also a list of potentially empty folders. The FDUPES tooling has such capabilities already. It only needs to be added to the existing container implementation.
From my perspective, it could even be the same container instead of creating a new one. Reason is, that many (if not all) settings & volume mounts etc. are the same here, but only the fdupes command is different. But on the other hand, another container would allow to limit the search. Sometimes, empty folders are created by intention to provide a base structure.

Describe alternatives you've considered
n/a

Additional context
It might require some restructuring again. The docker container is defined in a config folder. But it might either be a new repo or a separate folder docker within this repo.