[video-toggle] Add align option

[MiepHD]

Appended video-toggle to #main-panel so it can be centered over the video.
Centered it through setting left to 50% - 120px and set position of #main-panel to relative that it uses this to center.

[th-ch]

It works but (opinionated) I preferred having it on the side, it covers less the video 😄 Maybe we can have it as an additional css file, and make it a plugin option to center or not the toggle? This way users have a choice

[MiepHD]

You can now choose between left, middle and right

[Araxeus]

This can possibly break the plugin (and it did for me, multiple time)
Cannot read properties of undefined.
mainpanel.style.setProperty("--align", "0px");

this whole code block needs to be inside an apiLoaded closure, we can't guarantee that $('#main-panel') exists when this code is called

In other words, instead of being inside the default export function, it should be inside the setup function which is called only when the page is loaded

@MiepHD @th-ch plz fix

[MiepHD]

Hm.. that's right. I'll correct that.