883: Admin create user enhancement r=mergify[bot] a=cr1st1p
## What type of PR?
Enhancement
## What does this PR do?
It allows the admin docker image to also create the admin user.
The idea is that in my kubernetes setup, I do not want to manually do anything, as such, I need a way for the admin user to also be created automatically without me getting inside the pod.
So I had to change the manage.py function that creates the user to allow different 'modes' (me, I'll be using 'ifmissing') and also start.py to call that functionality if appropriate environment variables are present.
So now, in my Deployment, I add 3 more environment variables and I get the admin user created, IF not already present.
### Related issue(s)
none?
## Prerequistes
Before we can consider review and merge, please make sure the following list is done and checked.
If an entry in not applicable, you can check it or remove it from the list.
- [x] In case of feature or enhancement: documentation updated accordingly
- [x] Unless it's docs or a minor change: place entry in the [changelog](CHANGELOG.md), under the latest un-released version.
Co-authored-by: cristi <cristi.posoiu@gmail.com>
Co-authored-by: cr1st1p <cristi.posoiu@gmail.com>
Co-authored-by: Tim Möhlmann <muhlemmer@gmail.com>
This will make network configuration and host based authentication
more robust, across different deployment platforms.
The options `RELAYNETS` and`POD_ADDRESS_RANGE` are kept for compatibility.
However, their usage have become optional.
Allows to use mailu without docker-compose when hostnames are not set up
by docker itself but provided via a separate resolver.
Use case: use mailu using nomad scheduler and consul resolver instead of
docker-compose. Other servers are provided by the DNS resolver that
resolves names like admin.service.consul or webmail.service.consul.
These names needs to be configurable.
