Bug 235747: [registers] Allow user to edit the register groups.
Bug 235747: Move register group actions to the command framework.

Change-Id: Ife5aefc1a1609309724db01d92a35750e25def24
Signed-off-by: Alvaro Sanchez-Leon <alvsan09@gmail.com>
Signed-off-by: Marc Khouzam <marc.khouzam@ericsson.com>
Reviewed-on: https://git.eclipse.org/r/13980
Tested-by: Hudson CI