[deconz] add group support (#8715)

* add group message

Signed-off-by: Jan N. Klug <jan.n.klug@rub.de>

CODEOWNERS

@@ -44,7 +44,7 @@
 /bundles/org.openhab.binding.daikin/ @caffineehacker
 /bundles/org.openhab.binding.danfossairunit/ @pravussum
 /bundles/org.openhab.binding.darksky/ @cweitkamp
-/bundles/org.openhab.binding.deconz/ @davidgraeff
+/bundles/org.openhab.binding.deconz/ @J-N-K
 /bundles/org.openhab.binding.denonmarantz/ @jwveldhuis
 /bundles/org.openhab.binding.digiplex/ @rmichalak
 /bundles/org.openhab.binding.digitalstrom/ @MichaelOchel @msiegele