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.

首先定位 mode manager 及其 mode_inference 整合，接著追蹤目標狀態與目前狀態如何用於轉換。圍繞所要求的行為定義生命週期服務：它應處理已經到達的目標，以及需要在任意狀態之間進行多次轉換的目標。