This updates dockerfiles after recent changes to freeipa-builder containers:
freeipa/freeipa-builder@09cda09

- Add Dockerfile for Fedora 30 (ipa-4-8)
- Remove old dockerfiles (fedora 25 and fedora 28)
- Update Rawhide dockerfile

Signed-off-by: Armando Neto <abiagion@redhat.com>