Added -common, -xorg and -wayland subpackages

[faenil]

I have splitted nemo-mobile-session in three subpackages:

• common: has files needed by both configs (room for future improvement here, as I'm not sure which env vars and which files are X11 only)
• xorg: keeps x11 session files, pulls in xorg-launch-helper. This is the package current images will automatically upgrade to.
• wayland: Wayland specific files

It has been tested on an updated X11 image using "zypper dup --from" to bypass the vendor check.

We will have to edit patterns accordingly, pulling in nemo-mobile-session-xorg/wayland instead of nemo-mobile-session

[saukko]

These should not be needed, if this needs them all packages needs them so this needs to be fixed some other way.

[faenil]

Removed the tar_git fixes, it should not be needed on the official package.

The thing is, if you branch the official package on OBS, without making any modification, it doesn't build, and gives that "unknown tag" error, but with the same files it builds the official package, so it has to have something to do with resolution of tags, maybe my branched package is missing some configuration on OBS (I'm building against nemo:devel:mw)

Anyway, I deleted this commit because it shouldn't be needed for the official package, as it wasn't needed before (I changed nothing related to oneshot)

@saukko I'll wait for your ok and then merge and tag ;)

[saukko]

This will break UI on update if user doesn' install the xorg package as well. We need the nemo-mobile-session-xorg to obsolete nemo-mobile-session <= x where X is the previous version.

[faenil]

Added "Obsoletes: nemo-mobile-session <= 21" in the xorg package

[faenil]

Spent some time studying the packaging system, and I updated the PR, I think it's final now ;)

I will wait for a review before merging :)

[bwachter]

Looks good. Only thing I spotted was the invalid group, but that can probably be ignored at the moment.