ReadHandler and WriteHandler decorators

modules with a couple of parameters with similar read_* or
write_* methods may handle them by generic methods wrapped
with decorators ReadHandler / WriteHandler

The trinamic driver is included in this change for demonstrating
how it works.

In a further step, the special handling for the iohandler stuff can
be moved away from secop.server and secop.params, using this feature.

+ fix problem on startup of trinamic driver (needs MultiEvent.queue)
+ some other small fixes
+ apply recommended functools.wraps for wrapping

Change-Id: Ibfeff9209f53c47194628463466cee28366e17ac
Reviewed-on: https://forge.frm2.tum.de/review/c/sine2020/secop/playground/+/27460
Tested-by: Jenkins Automated Tests <pedersen+jenkins@frm2.tum.de>
Reviewed-by: Enrico Faulhaber <enrico.faulhaber@frm2.tum.de>
Reviewed-by: Markus Zolliker <markus.zolliker@psi.ch>

secop/params.py

@@ -196,7 +196,6 @@ class Parameter(Accessible):
             self.ownProperties = {k: getattr(self, k) for k in self.propertyDict}
 
     def __get__(self, instance, owner):
-        # not used yet
         if instance is None:
             return self
         return instance.parameters[self.name].value