Fix rules for rtai-config-<kver> script rename
Give bin/gencontrol.py argument to dump config

This helps a lot with debugging.

Also fix a couple of objects with broken or missing __repr__().
Allow templating pkg relation config fields

Use case is adding e.g. 'Provides:
rtai-modules-%(abiname)s-rtai.x86-686-pae' to a package.
Add 'Provides: rtai-modules-...' to RTAI kernel pkg

This adds compatibility with LinuxCNC project kernel pkgs.
Remove earlier 'Provides: linux-image-<featureset>' hack

The right way to do this is in the package config.
Add Provides: linux-image-<xenomai|rtai> to pkgs

Want this to be braindead-simple for other package relation
definitions