Check analog connections using nominal potentiometer values

[adeguet1]

We can use the potentiometer values to help identify the arm connected or at least make sure the values read make sense for the arm we're supposed to control. E.g. for ECM, only the first 4 values should be meaningful and should be within a specific range. For a PSM, the last pot is not used. For a MTM, all pots are used. This can be used to detect:

• which arm is connected
• faulty potentiometer
• overall connections issues (SCSI between QLA and dMIB) or Cannon ITT connection

See also #99