Support for a clinician to set the IDED-3D counterbalancing options for single user mode

[martinburchell]

We currently have support for per-patient task settings in the Patient Task Schedule editor (when editing a server-created patient) but none of the tasks currently support this.

One candidate is for the clinician to be able to set the IDED-3D counterbalancing options. e.g. something like:

{
    "ided3d": {
      "counterbalancing": "3"
    }
} 

It should be a case of implementing applySettings() for the IDED-3D task.