Add Maximum Allowed Video Transcoding Resolution

[TrickOC]

Describe the feature you'd like

Add option of maximum allowed video transcoding resolution, same as web and android client.
This could solve 4k playback issues on weak devices by keeping the maximum resolution at 1080p even if the device supports 4k. Like for example my Xiaomi Mi Stick.
Some related issues #2916 and #2516.

[alpargataman]

Same problem here. I have some 4K content with low bitrates (4mbps) and my firestick lite doesn't try to transcode the file, so it can't play that on the device.

[t0mas]

Similar for the "Chromecast with Google TV" device (the non 4K version). Jellyfin-androidtv tries to direct play HEVC 4k files, but the device can't hardware decode those. So Exoplayer shows a player error and external players (e.g. MX Player) try to play with a lot of stuttering at maybe 5fps.

It would require telling the server to transcode to HEVC 1080p to get these devices to play.