Stream during recording

[Lillifee]

Keep the stream active during recording. Feature request from disucussion https://github.com/Lillifee/raspiCam/discussions/40

Currently, libcamera-vid only supports a single stream at a time. This stream is recorded to a file during recordings and streamed live with different settings on the website. However, if we attempt to preview a 1080p video with a high bitrate, it will cause delays and lags in the live stream. Consequently, it becomes quite challenging to simultaneously record a high-quality video and stream it. In my opinion, the most viable solution would be to save the high-quality video to a file, compress it using ffmpeg, and then stream the compressed version on the website. However, implementing this solution may require significant refactoring since raspicam does not currently utilize ffmpeg.