new poll mechanism

- remove secop.poller and basic poller
- regular polls for 'important' parameters done by method doPoll
- all other parameters are polled slower (slowInterval) and
  with lower priority (only one at a time when main poll is due)
- nopoll decorator for read_* to disable poll
- enablePoll attribute (default True) for disabling polling a module
- fast polls may be implemented by means of a statemachine
- configurable slow poll interval
+ allow a Parameter to override a Property (parameter
  Readable.pollinterval overrides Module.pollinterval)

Change-Id: Ib1b3453041a233678b7c4b4add22ac399670e447
Reviewed-on: https://forge.frm2.tum.de/review/c/sine2020/secop/playground/+/27832
Reviewed-by: Enrico Faulhaber <enrico.faulhaber@frm2.tum.de>
Reviewed-by: Markus Zolliker <markus.zolliker@psi.ch>
Tested-by: Jenkins Automated Tests <pedersen+jenkins@frm2.tum.de>

secop_psi/softcal.py

@@ -160,9 +160,9 @@ class Sensor(Readable):
     pollinterval = Parameter(export=False)
     status = Parameter(default=(Readable.Status.ERROR, 'unintialized'))
 
-    pollerClass = None
     description = 'a calibrated sensor value'
     _value_error = None
+    enablePoll = False
 
     def initModule(self):
         self._rawsensor.registerCallbacks(self, ['status'])  # auto update status