Add Options for Versioning of NFO-Files, Saving of Cover Images and Genre Handling

[masterr2001]

Sorry, I messed with my Git Repo, therefore need to re-open an new PR. Sorry for the overhead.

I really love this Plugin, thank you very much for creating. I added some Options/Functions that I wanted to have:

I added an Option "versioning" that can save existing NFO-Files through versioning. If the Option is enabled and an NFO File already exists it will be preserved with an 3 Digit Number (movie.nfo -> movie.nfo.000) If you set "genre_parentname" to empty, tags that have no Children will be taken as Genres now I added an Option "saveposter" that can save the front_image (cover) of an movie alongside with the .nfo as "moviename-poster.jpg" I added an Option "onlymovie" that will make sure that nfos are only generated for scenes that have an movie linked to it I hope you find this additions useful.