Use mysql2 scheme for compatibility with Ruby mysql2 gem

See also https://github.com/Kloadut/dokku-md-plugin/commit/a2cb8392950d2b4d23c1a1cd53d7fb81d12a7ae4
Remove explicit loopback binding and access MariaDB on docker bridge IP

Keeping IP and port the same ensures DB connections survive reboots. kloadut/dokku-md-plugin uses this approach to fix IP but can’t fix the port since it starts multiple MariaDB servers.
Merge branch 'reboot-persist-connections'
Merge branch 'use-mysql2-scheme'

Conflicts:
	commands