Get rid of InstantCommand for cameras

[willitcode]

I hate inline creation of commands, so bye bye!

Turn this into a fully-fledged command class. This should be abstracted such that we can make multiple StartCamera commands for multiple different cameras though, so we do need to break our "no dependency injection" rule here in order to make the command flexible enough to allow for multiple commands.

Putting camera numbers in Constants is also in scope for this issue (and should happen).

[willitcode]

In do later because Heartland branch needs to get merged first