BXV (8.38) Temporarily duplicate ZebraConstantVelocityMoveController.

The aim is to create a ZebraRockScanMoveController temporarily in order
to make it clearer what the requirements are for abstracting out move
controller strategies.
BXV-115 (8.38) Create ZebraRockScanMoveController.
reduce compiler warnings
Merge -s ours remote branch 'origin/8.38+BLXV-115'