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.

.github/ISSUE_TEMPLATE/bug_report.md

@@ -65,13 +65,3 @@ If your log is very long, create a Gist instead (and post the link to it): https
 ```text
 LOG LOG LOG
 ```
-
-The output of `docker-compose logs nginx`:
-<!--
-Only if you have gotten a 5xx http error, else delete this section.
-If your log is very long, create a Gist instead (and post the link to it): https://gist.github.com
--->
-
-```text
-LOG LOG LOG
-```