Remove original omero Dockerfile
Add a Dockerfile for postgres
Add an all-in-one OMERO.server Dockerfile, requires omero-grid/db
Added a split server and processor configuration

Based on http://www.openmicroscopy.org/site/support/omero5/sysadmins/grid.html#nodes-on-multiple-hosts
Added an OMERO.web configuration
Added a basic README and some helper scripts to build/run