Use entry points for config generation

This starts using entry points to generate configuration for the
common.config and the common.wsgi modules, as they use entries with the
same name in different groups.
This also removes configuration for sslutils which is unused, and
re-enable the check for up-to-date configuration.

Co-Authored-By: ala.rezmerita@cloudwatt.com
Closes-Bug: #1288586
Change-Id: If48c62bbb2b1fb641791dad56f7f905e483080fa
Merge "Use entry points for config generation"