Reduce requests to Plex

[SpaceK33z]

Because of #1, if a movie doesn't exist on Plex with the given year, it will do a second request with the year + 1.

Perhaps we should use the search API for this. I didn't want to use it before, because e.g. searching for a movie like "50 cent" would also return all movies where "50 cent" acts in. However I just found it is possible to prepend title:.

Another benefit of using this search API is that we no longer have to keep track of the movie & TV show libraries, because the search API just searches in all of them.