* General code cleanup.
* All functions that return a characteristic or service have been renamed to have a `get` prefix to better represent their function.
* All functions that set a value have been renamed with the prefix `set` to better represent their functionality.
* Added an `bool notify` parameter to `setBatteryLevel`, which if `true`, will send a notification of the value to the peer.
- This changes NimBLERemoteCharacteristic::subscribe and NimBLERemoteCharacteristic::registerForNotify functionality
such that the notification callback will always be set.
Additionally these methods will always return true unless the descriptor write fails.
This allows for notifications to trigger the callback when a peer device sends them and does not have a CCCD.
Also it should not be flagged as a failure if the CCCD does not exist.
It should only be flagged when an acutal write operation fails.