reprganized docker file, less layers, new shortcuts for management commands

docker/management_script.sh

@@ -0,0 +1,15 @@
+#!/bin/bash
+
+set -e
+
+cd /usr/src/paperless/src/
+
+if [[ $(id -u) == 0 ]] ;
+then
+  sudo -HEu paperless python3 manage.py management_command "$@"
+elif [[ $(id -un) == "paperless" ]] ;
+then
+  python3 manage.py management_command "$@"
+else
+  echo "Unknown user."
+fi