Add Prowlarr instance support

[samuelporter]

This adds basic support for Prowlarr as a third instance type, and allows users to view and toggle indexers through the settings menu to control where content is searched and downloaded from.

Main changes:

• Prowlarr added as a new instance type
• Prowlarr instance view has an "Indexers" button which leads to an indexers view
• Indexers in the list view can be toggled on/off, or selected to show a details view with indexer info

As long as Prowlarr has been set up with Full Sync enabled for Radarr and Sonarr (this is the default), enabling or disabling an indexer should automatically propagate that change to both services.

I didn't add anything for adding/removing indexers, or tracking indexer health/status in any other way (#546). But those could easily be added on top of this.

I'm pretty new to Swift and iOS programming, so I'm sure this isn't perfect. But I've done lots of testing and it works well. I've also included a short demo video. Open to feedback!

Demo.mov

[tillkruss]

Hey @samuelporter, this is neat, but I'm not sure if its worth it since you can already filter search results by indexer.

If this would do full prowlarr searches it would be more useful imo.

wdyt?

[samuelporter]

Yeah that's fair, this does have a lot of overlap with search filtering.

I submitted this to solve a very specific problem I've had with searches being slow with lots of indexers enabled. It gives users a clean way to keep only one or two enabled at a time, and enable more on the fly if needed. But I know that's probably a niche use case. So I'm happy to add more to this to make it more broadly useful!

For Prowlarr searching, what would you expect that to look like, and what would make it different from the searches you can run in other places?

I could also look at adding support for adding/removing Prowlarr indexers, or showing more detailed statuses of indexer services like #546 mentioned. Those might fit more with the indexer management theme and would add more broadly useful functionality.

[tillkruss]

I submitted this to solve a very specific problem I've had with searches being slow with lots of indexers enabled

I've got 20+ indexers too and tend to disable ones with slow responses times. That seems like a Prowlarr issue tho, not a Ruddarr one. Maybe Prowlarr needs better timeouts or more simultaneous requests.

For Prowlarr searching, what would you expect that to look like, and what would make it different from the searches you can run in other places?

I sometimes want to search audio books or whatnot and use the prowlarr web UI directly. Selecting categories, etc. This would be a neat feature.

I could also look at adding support for adding/removing Prowlarr indexers, or showing more detailed statuses of indexer services like #546 mentioned.

I personally only manage indexers 1-2 a year, but seeing health messages like expiring VIP etc could be nice. Could also disable health messages from Sonarr/Radarr.

[samuelporter]

Cool, I'll look into adding some of those things to the PR this weekend. I haven't done a lot of searching with Prowlarr before (I've only ever done indexer management with it) so it should be a fun project.

[tillkruss]

@samuelporter happy to chat more on discord too if you like.