Add support for controlling DiSEqC GOTOX/USALS rotors

This adds support for controlling DiSEqC GOTOX/USALS rotors. If a rotor type is defined in the "Satellite config" table, dvb_fe_tune logic will be altered, ie appropriate DiSEqC commands will be executed (to control the rotor), a rotor_delay timer is armed, and after the timer is executed, the remaining dvb_fe_tune logic will continue.