Improvements for PV names

[henriquesimoes]

The original IOC has some issues with PV naming. Basically, they are:

1. RFFERst-SP: it does not follow the -Cmd suffix pattern for commands.
2. PID parameters:
   • Use PID instead of Pid.
   • Most PV names end with the board they refer to (either AC or BD). This however is not true for PID parameters, for instance RFFEPidACKp-SP.
   • Temperature constants are not the standard constants, even though they are named after them.
     See [BPMApp] Wrong meaning of temperature control PID parameters (Kp, Ti, Td vs. Kp, Ki, Kd) bpm-epics-ioc#35 and Misleading names for temperature control PID parameters rffe-uc-fw#5.
3. RFFEPidSp{,AC,BD}-SP: rename it to RFFETemp{,AC,BD}-SP directly, as suggested by Érico.