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...
* 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
