docker: move keygen-httpd container to F32
    
    It was previously based on very old fedora/apache image based on F25.
    That was causing several issues, including a broken installation of the
    `copr-keygen` package.
    
    Do dnf commands in one RUN statement to fixup cache bloat inside image.
    
    Define user's home directory while we are creating the user itself.
    
    Avoid apache listening on Port 80.  That one is already used by
    dist-git, and inside one podman-compose pod each port can be used only
    once.