* add thing definition with ID "smart-plug-compact"
* add constant for thing type UID
* extract abstract implementation for devices with power switch and
energy monitoring
* let in-wall switch handler and smart plug handler extend the abstract
implementation
* register new handler
* add method with boolean parameter to fetch initial state actively
* make BoschSHCDeviceHandler abstract
* add documentation
* add unit tests
closes#13528
Signed-off-by: David Pace <dev@davidpace.de>
71da06dac7