Prefer secret to env variable if both are configured

Remove the 'X-Forwarded-Proto' line from the nginx config ...

The reason is that in the default configuration nginx is only serving 'http' traffic.
So if an upstream proxy sets the 'X-Forwarded-Proto' header, because it is terminating
TLS, then nginx will overwrite it to 'http'. This will cause django to think the page
is served via 'http' and it will not create 'https://...' URLs.

Related to #292

Building the Docker image with Github Actions

Merge pull request #186 from netbox-community/non-root ...

Non root

Massive speedup in executing startup_scripts

set umask in entrypoint

fix typo

Introduce $SKIP_SUPERUSER ...

This adds a new variable to skip the creation of the superuser.
That is useful for LDAP and for production environments.

Fixes #160

Make startup scripts optional ...

To optimize the application boot time the startup scripts can now be
disabled by an ENV variable. The default when the variable is not set,
is to run the startup scripts. This means that the default behaviour is
not changed from earlier releases.

Remove deprecation warning for netboxcommunity images

Consistent variable use in build scripts

♻️ Make netbox-worker it's own container ...

One container should ideally have one responsibility [1]. Therefore I
implemented the netbox-worker to start in it's own container. This is
possible, because netbox and the worker communicate via redis anyway.

They still use the same image underneath, just the "command" they
execute while starting different.

Or in other words: I see no reason to introduce supervisord, when we
already have docker-compose which can take care of running multiple
processes.

Also, here's another benefit: Now it's possible to view the logs of the
webhook worker independently of the other netbox logs (and vice-versa).

Other changes in this commit:
* I don't see a reason to put a password for Redis in the docker-compose
  setup, so I removed it.
* Slightly changed the nginx config, so that the nginx startup command
  becomes simpler and any error should be visible in the docker log.
* Some housekeeping in the `Dockerfile`.
* Added some troubleshooting advice regarding webhooks to the README.

I'd like to thank Brady (@bdlamprecht [2]) here who did the harder
work of figuring out what's even required to have webhooks working. [3]

[1] 
https://docs.docker.com/develop/develop-images/dockerfile_best-practices/#decouple-applications
[2] https://github.com/bdlamprecht
[3] https://github.com/ninech/netbox-docker/pull/90

Update docker-entrypoint.sh ...

Make netbox-docker function with  v2.4-beta1 again, fixes #84.

> The shell --plain option is deprecated in favor of -i python or --interface python.
> The shell --interface option now accepts python to force use of the “plain” Python interpreter.
https://docs.djangoproject.com/en/2.0/releases/1.10/#deprecated-features-1-10

Fixed missing "

Added username and email of superuser

Do not print the admin credentials. All outputs from STDOUT may end up in a central log store. This will compromise the superuser credentials.

Move config to /etc/netbox/config (Fixes #54) ...

With this the configuration is moved to /etc/netbox/config and the
default reports directory is set to /etc/netbox/reports. This enables
the user to mount reports from a config map or persistent volume in
OpenShift.

Externalize gunicorn-config ...

This moves the gunicorn_config.py into /etc/netbox so that it can be
easily mapped through a Openshift config map

Add django_ldap_auth ...

In the ldap.Dockerfile the django_ldap_auth module is installed to
enable authentication againt LDAP servers.

Modifications for Openshift ...

With these modifications the netbox containers can run on Openshift.
The configuration files can be imported from a config map to the
'/etc/netbox' directory and will be loaded from there.

✨ Include Initializers ...

Initializers are startup scripts for common tasks like creating custom
fields. These are problems many users of Netbox Docker potentially face
and are therefore worth sharing.

Load custom fields when creating the container.

🐞 Convert numbers from ENV to int ...

Fixes #36

❇️ Make the default configuration cluster ready ...

This changes the default configuration to be better prepared for
usage with container management platforms, such as Docker Swarm,
Kubernetes or OpenShift.

Closes #27.

Merge branch 'master' into Allow-setting-ENFORCE_GLOBAL_UNIQUE-in-env

Allow setting ENFORCE_GLOBAL_UNIQUE in env

Merge branch 'master' into Enable-uploading-of-images

Enable uploading of images ...

Set client_max_body_size to 10M so that we can upload images

✨ Creates a token for admin by default

🐞 The upstream repo remove the docker config ...

.. so I copied it over to this repo.