[script_server] allow to specify vel and acc for each movement

[HannesBachter]

currently sss.move gets vel and acc from the parameter for each movement. If you like to use different vel and acc you need to set param, move and reset param.

an enhancement would be to enable setting vel and acc in the sss.move command directly. This needs an API update of sss.move.

CAUTION: an API update will also influence command_gui (knoeppkes)