MS Windows native webcam capture

[totaam]

Split from #1231.
The opencv version breaks regularly and requires a huge list of dependencies.
It should be possible to capture frames with a fairly simple cython wrapper.

Perhaps something similar to:
DirectShow Virtual Video Capture Source Filter in C#

[totaam]

Removing this huge list of unused dependencies will also avoid vulnerabilities in those libraries, such as CVE-2023-51257
(we are not vulnerable in any meaningful way - but rather than having to explain why, just avoid the issue altogether)