Use Picture in Picture to pop out the Timer

[CryZe]

https://developer.chrome.com/blog/the-future-of-picture-in-picture/

[CryZe]

The initial implementation does not use the picture in picture API, just window.open(). That works on all browsers. We can revisit the picture in picture API at some later point.

[CryZe]

It's now using the Document Picture-In-Picture API if it's available: #1047