#24 Feature Request: Add Support for File Services

[prof-m]

Noticed that the dupe finder was always targeting 'all local files', so I took a crack at adding a basic new CLI option for targeting a specific file service.

Most context can be found in issue #24

@appleappleapplenanner I'm not married to any of this, and it's been a hot sec since I wrote serious Python code, so more than happy to make changes both functional and stylistic if there's anything you want to see differently. Also no rush to review this! It's is running well on my local machine, so I'm in no hurry.

[appleappleapplenanner]

I changed a few things setting up for multiple file service keys, cleaned up error handling, and fixed an error in config.py where the default file service was set to "my tags" which I assume you git ignored because you were using your own file service.

Merge my changes, test them, and if you don't have any errors I'll merge into main

https://github.com/appleappleapplenanner/hydrus-video-deduplicator/tree/prof-m-file-service

[appleappleapplenanner]

I fixed an issue with my branch with default inputs, you probably need to remerge.

[prof-m]

@appleappleapplenanner One more pseudo-fix - aa10b9b

[appleappleapplenanner]

Finished up my changes, if they all work for you I'll merge. Give unions a test just for good measure, with and without queries. They worked for everything I tried.

[prof-m]

@appleappleapplenanner Apologies, I was off traveling, but thanks for merging this in! My testing (with unions on file services and unions on queries) worked as expected 👍🏼 Glad I could contribute!