Independent camera group triggering

As of PR #14 we have a single triggered camera controller controlling 3 behavior cameras in the rig. These cameras are triggered across 2 separate behavior board lines (2 cameras on 1 trigger line, 1 camera on the other trigger line). As these cameras are all defined under the same controller, we cannot currently define independent trigger rates for these camera groups.

We'd like to instead map these camera groups according to the trigger line they are on, this means being able to define multiple camera controllers where we can set the frame rate independently between them.