Changed Dockefile to Dockerfile

* merge docker makefile into main one

* add readme for docker folder

* don't include a file that doesn't exist anymore

Co-authored-by: Lauris BH <lauris@nix.lv>

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>

- Created a Container options section in `docker/README.md`
- Add documentation for SOCAT_LINK
- Move CROND documentation to the new section

minor grammar fix

- Remove the known issue about `.dockerignore` being ignored during DockerHub automated build as this has been fixed
- Added a note on the fact that we currently do no support building the container on RPi1

- Now using a setup script before starting the app. The separation of
the run script and the setup script will make service initialisation a
little bit clearer
- Now calling start.sh script as ENTRYPOINT and S6 as CMD. This way
when running the container with just a shell script, the start.sh
script will be launched before, making debugging easier
- Added note about `.dockerignore` ignored during Docker Hub Automated
Build

Shrink docker image.
Update from fig (deprecated) to docker-compose.
Update README.md.

Signed-off-by: Tiago Pires <tandrepires@gmail.com>

Rewrite of the docker setup. Now uses fig to manage containers and container
linkage. The base is a block based mix and match, which will give you the
possibility to easily test all configurations.