Plexrequests should have its own API queue

Nobody has claimed this yet.

I maintain a large plex server, with 80 users and 100TB of storage. My sonarr instance is frequently busy, and it appears that during active periods the sonarr api doesn't respond to external api requests while it is busy doing other things. The end result is that a user might request something via plexrequests, and upon clicking the button to request, the "requesting..." button just sits there with a spinning graphic until sonarr can respond.

Granted, I might not have the most common use-case for plexrequests, but it would be sound programming for plexrequests to maintain a queue of its own for the times where sonarr may not be able to (timely) respond to a request.

My plex/sonarr/plexrequests instance is available to any of the devs if you are interested in troubleshooting this scenario. Hit me up on here, in #Sonarr (freenode irc) or at support@notflyx.com.

Start by tracing how plexrequests sends requests to Sonarr and how the request button reports progress; the issue provides no file or test entry point. Done should mean Sonarr requests are queued by plexrequests during periods of slow response and the user-facing request eventually completes instead of remaining indefinitely in a loading state.

Written by the indexing model from the issue text.