Disable Shib if not needed; add env var checks
If AUTHENTICATION=internal we avoid loading mod_shib and starting shibd.
Also added environment variable checks so if some are missing due to
wrong Docker composition, midPoint will inform user in a reasonable way.
Do naming cleanup
Environmental variables and container names are improved.
Only demo/simple is OK now; other ones are inconsistent now.
Add auto-upgrade support
Adapt directory structure to docker/util
The container is now built directly from the root directory.
Even the simplest composition was moved to demo/plain.