Remove port from registry URL

backup-rotation/Dockerfile

db-backup/Dockerfile

mattermost-cleaner/Dockerfile

old/checkmk/Dockerfile

old/framadate/Dockerfile

old/galette/Dockerfile

old/minetest/Dockerfile

old/mysql-backup/Dockerfile

old/pica-apache/Dockerfile

old/pica-kanboard/Dockerfile

old/postgres-backup/Dockerfile

pica-bot/Dockerfile

pica-nginx/Dockerfile