MUONFE: Add alarms to the IOCs

From James:

I was wondering if it's possible to set up alarms on IBEX. I had a look on NDEMUONFE and while there is an "Alarms" page there are no alarms showing and no obvious way to set one. Do I have to log in as manager? Genie_python only has a g.check_alarms() function which returns with an empty list meaning "all OK" but no way to set any. (Setting Run Control is different, I can do that following last week's course)

I have two applications for alarms:

- on MUONFE, after setting the magnets up at the start of the cycle and completing any beam tuning I set alarms on them at the current setpoint +- some tolerance for noise. Then if a magnet goes out of range (including going off completely) we get an alarm and can investigate.

- on the muon instruments once they're running under IBEX. In the "settemp" command we already use in SECI, and will probably rewrite in python, it will do the following (new actions marked **):
- ** set the alarm limits on the temperature to a wide range spanning the current value, the new setpoint and an allowance for overshoot (but if it goes way beyond the target and keeps going we get an alarm straight away)
- look up PID values, heater power range, etc appropriate to the new setpoint and cset() them
- cset() the new setpoint
- wait for the temperature to reach a stable value within some band and stay there for a certain time, but with a timeout
- ** set the alarm to a narrow band around the new value (so we get an alarm if it drifts off mid-run, or straight away if the target was never reached).
- return control to the main script.