Provide lifecycle servicing

The mode manager usually knows the **target** state/mode and the **current** state/mode (via mode_inference) of a system or node. Currently we assume, that there is a trivial transition to the target state, e.g, _activate_ to go to active, _deactivate_ to go to inactive.

However, this is not always true, e.g., if actual state is already the target state, or if target state can only be reached with >1 transitions. In order to allow that, mode manager needs to implement some kind of lifecycle service that knows how to get a node from any state to any other.

Start by locating the mode manager and its mode_inference integration, then trace how target and current states are used for transitions. Define the lifecycle service around the requested behavior: it should handle already-reached targets and targets requiring multiple transitions between arbitrary states.

Written by the indexing model from the issue text.