feat(base-app): Add docker setup

Adding a dockerfile as well as an `entrypoint.sh` file for deployment
using `gunicorn`.

.docker/entrypoint.sh

@@ -0,0 +1,5 @@
+#!/bin/sh
+
+# Start Dash and run in background
+echo "Starting Dash app..."
+poetry run gunicorn app:server -b 0.0.0.0:8000