Nginx reverse proxy combined with Starman server in one image (#46)

* feat: provide image with nginx

* Re-use parent container configuration and startup scripts

* Rewrite proxy Dockerfile:

* ARCH used to be hard-coded; is now set according to the architecture being built
* Build from the associated LedgerSMB base image (not from 'lsmb-split')
* More deletion of non-required files (/usr/share/doc/*)
* Fewer layers by combining RUN commands

* Use 'server-start' script generated by the installer instead of repeating ourselves

* Don't expose the status module

It won't be accessible anyway: the localhost address is the one inside the container...

* Ensure relative redirects

When the container port :80 is exposed as :8080 on the host,
nginx redirects to http://localhost:80/login.pl with a relative
path, instead of http://localhost:8080/login.pl; the container
isn't bound to :80, so that request fails...

* Rename proxy layer image

* Adjust 'build' script to publish base and regular images

---------

Co-authored-by: Walid Mujahid <walidmujahid@gmail.com>

base/start.sh

@@ -0,0 +1,6 @@
+#!/bin/bash
+
+home_dir="$(dirname $(readlink -f $BASH_SOURCE))"
+"$home_dir/config.sh" || { echo "Failed configuration" ; exit 1 }
+
+exec "$home_dir/run.sh"