Rework stack mode state machine for simplicity

The stack mode statemachine has actions defined for each state change where in fact it would be sufficient to just have one action defined for each state which is performed on entry of that state.

Also, there is a strict order of state transitions:

   +---------+    +---------+    +---------+    +---------+
-> |         | -> |         | -> |         | -> |         |
   | Offline |    |  Stop   |    |  Idle   |    |   Run   |
   |         | <- |         | <- |         | <- |         |
   +---------+    +---------+    +---------+    +---------+

So, for instance, a transition from Run to Offline should be transitive: Run->Idle->Stop->Offline, i.e. executing each entry action of all the states between the current state (excluding) and the target state (including).