Add Webcam GUI Tab

[spooknik]

Is your feature request related to a problem? Please describe.
Prusa printers lack a live webcam feed and rely on snapshots uploaded to Prusa Connect. However many users have a webcam streaming for real time monitoring. Prusaslicer already has web views for Printables, Prusalink and PrusaConnect, I suggest adding another webview that allows for viewing of a live stream.

Describe the solution you'd like
Adding a tab called "Camera" to the GUI tab which would display a camera live stream.

Describe how it would work
As an example, octoprint uses µStreamer by default and opens an MJPEG streamer. MJPEG streams are support in html5. Under the Physical Printer settings, there could be an option to insert a camera stream address. For example: http://20.20.20.20:8001/stream. Other protocols could be supported as well.

Describe alternatives you've considered
The obvious argument against this is that the live stream can be viewed in a browser, which is true. But Printables can also be viewed in a browser, but it's a huge gain to UX to have everything in the same app and have PrusaSlicer be the only thing you need open to monitor your print.

Additional context
N/A