vout: Use a fair display lock and interrupt wait

This merge request is a draft based on my proposal of the TC discussion. This is what was discussed during the workshop plus Romain's clock interruption.

~~While this particular MR doesn't try to execute the resize function in a background UI thread, my tests on a karaoke MKV with "-I dummy -Vopengl" on a 10 years old bad laptop already show promises.

I was never stuck in a window_ReportSize() callback for more than 16 ms (ie my screen refresh rate) in the most extreme case and usually stay under the 500 us so I wonder if there is an actual need to add a background thread to not block the UI.~~