Option to name file movie-trailer.ext

[bozrdang]

Seeing as how this script is intended to be used with Radarr, which is usually configured to upgrade the movie quality over time, and many people also configure Radarr to append quality info to the file name, it seems like it would be useful to allow users to configure TrailerTech to simply name trailers movie-trailer.ext rather than moviefilename-trailer.ext.

AFAIK most media software (Kodi, Emby, Plex) recognizes movie-trailer. Allowing this option would avoid the situation where the trailer name no longer matches the movie file name after it's been upgraded one or more times. Example:

300 (2006) - DVD-trailer.mkv
300 (2006) - Bluray Remux.mkv