Create example working configuration files for popular webcam models

[andyjack]

Thank you for creating this project! I found it while trying to get a C922 to work with my own small script that streamed video using cvlc, but I ran in to the issue with the C922 not making its H264 stream available in an easy-to-use way (unlike the C920).

I wanted there to be ready-to-use configuration files for my C920 and C922 models, so I created this pull request. I've tested both on my RPi 3B+ and can get a 1920x1080 30 fps stream (video only) with minimal CPU usage and latency.

For both cameras, I got ~1 second latency with uvcx_h264_i_frame_period = 1000 setting. It is possible to set it to the minimum value of 0, but this led to the webserver stream loading and spinning forever, although loading /stream.mp4 in VLC was fine. So I went with the next-highest allowed value of 1000.