* Add disable registration as an environment variable

for docker

* Add REQUIRE_SIGNIN_VIEW as env var to docker

* Add variables to template

* Update docker docs

* If using a different $USER then rename git user

* Chown based on $USER env

* Target only one part of passwd

* su-exec based on $USER

not a hardcoded value

Why:

* We are using self-signed ssl certificates for internal services, which results in failures when gitea tries to communicate through webhooks with these. We would like to enable gitea to be able to use these certificates without having to build custom docker images.

How

* We add the internal certificates to /usr/local/share/ca-certificates on the host
* We read-only mount /usr/local/share/ca-certificates from the host to /usr/local/share/ca-certificates in the container 
* We do a update-ca-certificates in the alpine container before starting gitea

This should have no consequence for users that do not have the need to handle self-signed certificates, as update-ca-certificates should be idempotent.

* Add `gettext` dependencies as we need `envsubst` command;
* Modified s6's gitea setup script, instead of `cp` the template if no
`app.ini` exist, it will substitude the envvars and generate the new
`app.ini`;
* Make `/docker/etc/templates/app.ini` a template contains environment
variables;

Signed-off-by: Tao Wang <twang2218@gmail.com>

Signed-off-by: Tao Wang <twang2218@gmail.com>

* Added stupid docker task to makefile

* Dropped unknown option PrintLastLog from docker ssh config

* OpenSSH should log to docker stdout

* Set random pw for docker git user, otherwise it is locked

* Stop using templates and public within docker

I have restructured the docker build process entirely, the binary gets
built outside of the docker build command, now we are managing all
dependencies with real Alpine packages and I have dropped features like
socat or the cron daemon.

Signed-off-by: Thomas Boerger <tboerger@suse.de>