Remove raspicam documentation

[lurch]

MMAL is no longer supported in Bookworm, which means the old raspistill / raspivid / etc. commands will no longer work.
https://www.raspberrypi.com/documentation/computers/camera_software.html#raspicam-applications

Should just leave a NOTE that if users really want to use the legacy camera applications, they'll need to use Legacy OS (which will become Bullseye, once Bookworm has been released).

[JamesH65]

End of an era! Those apps are 10 years old this year!

[lurch]

🎂

[lurch]

Also need to remove any parts that talk about using raspi-config to enable the camera, as I believe that's no longer necessary.

[lurch]

Merged to bookworm branch.