Initial contribution of thing concept.

Bug: https://bugs.eclipse.org/bugs/show_bug.cgi?id=433994
Also-by: Oliver Libutzki <o.libutzki@external.telekom.de>
Also-by: Kai Kreuzer <k.kreuzer@telekom.de>
Also-by: Michael Grammling <m.grammling@external.telekom.de>
Signed-off-by: Dennis Nobel <d.nobel@external.telekom.de>
This must not be WARN level, rather only TRACE.
And it should read "not supported by ThingHandlerFactory {thingHandlerFactory}".
But possibly it is best to completely remove this logging.