Move device configuration into ics_config product.

The XCU, CCD, and HX actors all either have or will have device configuration which needs to be tracked. Examples:

• per-ccd bias offsets, other voltages
• per-motor ranges and limits
• current thresholds to track
• temperature/power/etc setpoints
• many others.

These should not be in the code products. Much of it currently is.

Can this list be fleshed out by LAM? Any design comments welcome.

I'll start by proposing a tree of YAML files, one directory per actor, and one configuration item per line. I'm imagining a "default" configuration file, plus overrides.

I'll point out that this might be the place to declare alarm thresholds, and perhaps everything which is currently in the hated ics_xcuActor/etc files. Also, the PFI configuration should not be part of this.