Gunicorn is replaced with nginx-unit

We now serve Netbox with an nginx-unit instance instead of Gunicorn.
This allows us to get rid of the extra Nginx container because Unit is
also serving the static files. The static files are now collected at container
buildtime instead of every startup.

docker/docker-entrypoint.sh

@@ -7,6 +7,9 @@ set -e
 # Allows Netbox to be run as non-root users
 umask 002
 
+# Load correct Python3 env
+source /opt/netbox/venv/bin/activate
+
 # Try to connect to the DB
 DB_WAIT_TIMEOUT=${DB_WAIT_TIMEOUT-3}
 MAX_DB_WAIT_TIME=${MAX_DB_WAIT_TIME-30}
@@ -60,9 +63,6 @@ else
   echo "import runpy; runpy.run_path('../startup_scripts')" | ./manage.py shell --interface python
 fi
 
-# Copy static files
-./manage.py collectstatic --no-input
-
 echo "✅ Initialisation is done."
 
 # Launch whatever is passed by docker