Add PATH option to recognize:classify command

Describe the feature you'd like to request

Ability to limit occ recognize:classify to a single path.

Describe the solution you'd like

Something like other apps have :
occ recognize:classify --path="/username/files/MyFolder/"

Describe alternatives you've considered

Running occ recognize:classify again on the whole server, but that takes hours and hours just to go through the photos that are already indexed and classified.

Alternative could be something like occ recognize:classify --new which would skip all the files that have already been classified.
(or making this default behavior for occ recognize:classify and adding something like occ recognize:classify --force to force re-scan/re-index/re-classification of whole server)

I do realize this app is now on the "limited effort" maintenance, but hopefully someone picks up the task eventually...

Start by locating the occ recognize:classify command entry point and reading how it selects files for classification. Add a path-limiting option matching the requested usage, then verify that classification is restricted to the selected directory without changing whole-server behavior.