Option to pick anidb instead of scene mappings in thexem

[Guslletas]

Currently medusa uses scene mappings from thexem but some of the scene follows tvdb mappings and other follow anidb mappings so thexem mods have to pick which one is the "official" scene mapping for each show, this means some scene groups are never picked by medusa but this could be fixed by adding a per show setting allowing to pick whether if scene mapping or anidb mapping should be used for a show. With this and being able to manually add some aliases for each anidb season like we can do for the current mappings(since thexem aliases probably would only work for their scene mapping) medusa should be able to pick way more releases. One example would be this show: https://thexem.info/xem/show/5211, some scene groups like Erai-raws(which is one of the most relevant) are releasing the show by following anidb but other groups like SubsPlease(which is also very relevant) are using thetvdb numbering and thexem mods decided to side with the later. This means medusa can't pick erai-raws releases and even mixes seasons(it can pick season 2 episode 1 as season 1 episode 1) but by simply making medusa use thexem anidb's mappings instead of the scene ones the problem would be fixed.