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