[!!!][BUGFIX] ConfigurationManager signal information missing

The signal emitted in the ConfigurationManager of the ExtensionManager
misses crucial information (the extension for which the configuration
was written) and is therefor useless at the moment.

Add the extension key to the signal so that it may be used.

Change-Id: I21d22b10852e9842d9d077eb5dd49ec4518ca4ed
Fixes: #60609
Releases: 6.3
Reviewed-on: http://review.typo3.org/31773
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Helmut Hummel <helmut.hummel@typo3.org>
Tested-by: Helmut Hummel <helmut.hummel@typo3.org>