config/dspace.cfg: Add our config changes

We had been using special local dspace configs (due to passwords, etc),
but DSpace 3.0+ introduced the ability to use build properties, ie
dev.properties and prod.properties.

Make sure to configure/copy build.properties and then specify the
environment using maven, for example:

mvn -Denv=test package

This will package DSpace using the test.properties file in the root
of the DSpace source.  By default it uses build.properties.