* Support custom IP camera
Allow adding custom IP camera source while keeping possible
built-in bambulab camera also functional and add button to
switch between them.
This uses WebView widget to show the stream. Upon loading the
page, javascript is used to remove native controls and scroll-
bars for aesthetic reasons.
* Add partial support for PiP video
HTMLVideoElement supports picture-in-picture video
but the dedicated control is hidden in this implementation
to have more integrated look in OrcaSlicer. Add right-click
listener to the camera switch icon that opens the video element
in a PiP window.
Only works when the video is in <video> HTML element, so for
example MJPEG streams in <img> element won't work.
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