RoIs as counters

The counts of the RoIs defined in the MCA8715, MythenRoIs, Mythen2, EigerPSI, SIS3302, AmptekPX5, KromoTX1easyXAFS and PSCameraVHR Tango devices can be used as counters in Sardana. The same happens for the counts computed by the device of the class RoiCounterDeviceServer running in the LimaCCDs Tango Server and the Pilatus RoIs computed via VcExecutors, as described in 4.4.10. RoIs for the Xspress3 can be defined in a countertimer controller impolemented for this purpose.