Allow to set custom settings for embeded videos

[dimqua]

Since embeded videos do not respect user-defined settings such as default subtitle settings, it's probably a good idea to implement a possibility to set user settings without using cookies, e.g.
https://www.invidio.us/embed/XXXXXX?sub=en,ru&speed=1.5

Such URLs can be used by user.js scripts for embeding invidious videos.

[omarroth]

Currently you can set autoplay, loop, and quality for embedded, I like the idea of setting without cookies, and only doing them as params, which would need to include subs, speed, volume.

[omarroth]

7fd0f93 adds support for preferences as query params. It exposes:

• speed (e.g. &speed=1.43)
• volume (e.g. &volume=85)
• subtitles (e.g. &subtitles=en,ru,es)

You can use all of these on the /watch page as well. They will override user preferences if you're logged in.