Fixes season pack and episode only searches
Added per-provider options search mode and search fallback.

Search mode allows you to choose season packs only or episodes only which controls how backlogs search for data.

Search fallback if selected will attempt a 2nd search this time using the alternative search mode to see if it can get results if the previous attempt failed.

Provider settings are now read and stored dynamically instead of always having to retrieve them by there static names, this will allow for dropping in new provider modules easier to intergrate with existing options already present.

Fixed search code to not perform dupe searches by mistake.

Cache stores a list of shows we have rejected so that next time around we don't have to process them to know we don't like em.