[DockerApi] Rename DockerApi to Controller and add mailcow-adm tool

data/Dockerfiles/controller/docker-entrypoint.sh

@@ -0,0 +1,9 @@
+#!/bin/bash
+
+`openssl req -x509 -newkey rsa:4096 -sha256 -days 3650 -nodes \
+  -keyout /app/controller_key.pem \
+  -out /app/controller_cert.pem \
+  -subj /CN=controller/O=mailcow \
+  -addext subjectAltName=DNS:controller`
+
+exec "$@"