Split root component in installers into separate conf

No need to rewrite the root conf for every installer.
Reuse only one copy.
Add ThirdPartySoftware_Listing.txt separately into installers.
ThirdPartySoftware_Listing.txt should not be shown in the license
agreement page of the installer. It just needs to be installed under
/Licenses directory.

Change-Id: I268c6255145ed35a327037e1ef0c934b49037b99
Reviewed-by: Iikka Eklund <iikka.eklund@digia.com>