Re-introduce Vendor customizations through packaging

[packaging] Mer vendor customizations at RPM build time
Enable connman during packaging

[packaging] Enable connman support in configuration file
Force repo refresh in pk_backend_refresh_cache

This is in line with what most other backends do: When a refresh
of the cache is requested, we want to force a cache update. The
command-line "pkcon" client doesn't provide a way to set force.

[backends] zypp: Force repository refresh
Use zypp_perform_execution for system upgrades

Simplify backend_upgrade_system_thread by re-using
zypp_perform_execution and adding a new execution type UPGRADE. This
adds transaction features such as download-only mode and simulation
to the upgrade-system command, and enhances error reporting in case
of resolver issues (existing implementation zypp_perform_execution).

[backends] zypp: Use zypp_perform_execution for system upgrades
Do not consider satisfied patterns "installed"

Patterns can not be "installed" as such - they can only be satisfied
if all their dependencies are installed / satisfied.

Installing a pattern means trying to satisfy its dependencies.

Change the logic by which packages are filtered, so that patterns are
never considered "installed", even if their dependencies are satisfied.
This way, re-installing a pattern becomes possible, and will make sure
all current dependencies are satisfied.

The drawback of this is that now we can't use PackageKit to check if
a pattern is satisfied or not. Fixing this would require modifying the
code in zypp_emit_filtered_packages_in_list(). The comment there says
that emitting the same version of a package as INSTALLED and AVAILABLE
is not possible due to a PackageKit quirk.

For normal packages, this won't be a problem, as the installed package
will have some old version and a possible available update for that
package will have a different version. For patterns, however, even
though they are versioned, the pattern version at which the pattern was
installed isn't recorded(?), so we cannot emit the old pattern version
as INSTALLED and also emit the new pattern version as AVAILABLE.

Add some logging of filters in backend_get_packages_thread() to aid in
debugging similar filter-related issues in the future.

[backends] zypp: Do not consider satisfied patterns "installed"
Merge pull request #2 from thp/vendor-packaging

Re-introduce Vendor customizations through packaging
Merge pull request #3 from thp/refresh-fix

Force repo refresh in pk_backend_refresh_cache
Merge pull request #4 from thp/reuse-perform-execution

Use zypp_perform_execution for system upgrades
Merge pull request #5 from thp/pattern-reinstall

Do not consider satisfied patterns "installed"
[packaging] Build and package man pages
[packagekit] Add pattern and dist upgrade support
[packaging] Disable doc generation again, since !$%^ downloads stylesheets during build