Better Connection Management

[eely22]

First reported here: https://neighborhood.bluz.io/t/timing-question-possible-to-get-an-uninterrupted-window/558/6

The BLE states and commands make it somewhat difficult to easily manage the connection. For example, if the user wants to turn off BLE, they must call disconnect, and wait for the state to change to Advertising and then call stopAdvertising. This could also not work at times if the gateway connects before the app turns off advertising.

Need a way to turn off the connection entirely and also a way to track the states better.