This is necessary due to argon2 being added and an upstream issue where it uses
a Linux build that is too new for CentOS 7.

Deleted "Publishing A Release" section from the readme.md file in the 'ci'
folder and then pasting the section in 'Maintaining.md'

Co-authored-by: NAkash Satheesan <akash@coder.com>

New extraInitContainers configuration added.
It allows to pass template with a list of containers to execute before
main code-server container started. Main container will only start when
all init containers are  completed (exited with 0 code).

 Additionally changes the way extraContainers is used - instead of
 toYaml use tpl, because this allows to
 reference any values from extraContainers string.

* Update versions
* Update changelog

This ensures the link is correct. Should fix #3355.

* Check the logged user instead of $USER

Given that `sudo usermod --login "$DOCKER_USER" coder` and `sudo groupmod -n "$DOCKER_USER" coder` modify the container's disk it'll persist across restarts, but environment variables will be reset to whatever state they had at the end of `Dockerfile`. In this case, `$USER` is set to `coder`, so this branch will always be true.

By checking with the output of `whoami`, which gets it's information from `/etc/passwd`, we make sure to get the real logged user and not the one defined by $USER.

We also move `USER="$DOCKER_USER"` out of the branch, since we always want this to happen at entry-point. If we don't do this assignment, $USER will contain `coder` upon restart.

* Update entrypoint.sh

Check `$DOCKER_USER` was defined before copying it to `$USER`.

* chore(ci): remove unmaintained images
* chore(ci): update publish workflow