Allow stream component only for specific cameras in configuration

As described in more detail in this thread, different combination of generic, ffmpeg, and streaming turned on or off create very different results in the frontend. The stream component often delays cameras for 10 seconds, but is usually easier to get to display correctly in the frontend without the camera feed breaking.

But without the stream component, you can get a better realtime feed. It would be a big advantage if we could apply the stream component only to some feeds while other feeds could be left with the classic MJPG type presentation. In this way we could use stream for devices that don’t cope well with MJPG presentation but where the delay is acceptable, while also having faster feeds via MJPG for things that are time critical.

So, let’s have the best of both worlds and apply the stream: component only to cameras where we specifically request it, and let the other ones use the classic MJPG streaming, so we can combine both and use whichever one works best for the application we need in our config.