Integrate other services like simkl, TMDB watchlists

[jo-chemla]

Given the recent model switch for trakt.tv, which now limits free-users to 100 items lists, it would be great if Jellyfin team could port the trakt.tv plugin to other services like Simkl, TMDB/TVDB watchlist etc. The same feature-set would be amazing, updating watchlist, watch status and history, from and to the corresponding service to and from jellyfin.

Regarding the simkl plugin, there is another thread opened for feature-parity with the trakt.tv plugin here jellyfin/jellyfin-plugin-simkl#46