[Feature] Support for motion_sensitivity and occupancy_timeout using Eve characteristics
After #18 is finished (or during #18), it would be possible to expose the `motion_sensitivity` and `occupancy_timeout` properties via the same characteristics as used by the Elgato Eve Motion Sensor (as described in [this gist](https://gist.github.com/simont77/3f4d4330fa55b83f8ca96388d9004e7d)).

Service - Characteristic     | UUID                                 | R | W | Type       | Description
-----------------------------|--------------------------------------|---|---|------------|-----------------------------------
Sensitivity                  |E863F120-079E-48FF-8F27-9C2605A29F52  | x | x | UInt8      |0 = high, 4 = medium, 7 = low. Set in Eve.app
Duration                     |E863F12D-079E-48FF-8F27-9C2605A29F52  | x |  x| UInt16     |Persistence of motion indication in seconds. Set in Eve.app

The Sensitivity characteristics may also apply to the `sensitivity` property.