Split collections prism with migrated client

• Includes changes from !60 (closed) and on top:
• Creating new collection configurations: sace_emg csea_emg frtx_emg demF and their respective compose files
• follows work on pvs_starter in bringing templates up to date - EMG + VHR18 configurations can be created out of the box (except for fullresolution cache in vhr18, but that is non-standard), DEM mapcache & registrar need to be still copied from current config and renamed accordingly because of customizations
• moves env/.env to config//.env
• shibboleth access rules templating - uses just 2 env vars in shibauth
• update of client configs containing polygon labels
• do not stretch thumbnail only into width