Initial changes for the Fedora purposes
- switch FROM against fedora:25
- drop MAINTAINER statement, deprecated by docker-upstream docs
- install system-wide postgresql packages
- install findutils (for the purposes of fix-permissions)
- don't play with localedef (not needed now in F25)
- s/yum/dnf/
- drop SCL hacks from Dockerfile, and drop 'scl_enable' script