[Enhancement]: Ability to auto delete audiobooks when finished

[Doppelgangsta]

Describe the Feature/Enhancement

Have a toggle in the settings to have the ability to auto delete the files of an audiobook when you have finished the book.

Why would this be helpful?

Sometimes I forget to purge my phone of unneeded files. This would help people who are forgetful and do not have large phone space. If this is a toggle it would also be good for people who do not want it to be auto deleted leaving the manual task still there.

Future Implementation (Screenshot)

In other apps, you can have this toggled in settings.

Audiobookshelf App Version

Android App - 0.9.76

Current Implementation (Screenshot)

New user and I have another app that has this feature. So while setting up settings, I noticed this feature wasn't available.

[advplyr]

Duplicate of #293