Experimental RPM support and restructuring of installer-linux

This commit introduces RPM packaging for Neo4j.  It also moves around
the Maven module hierarchy to collect all the linux packaging under
installer-linux.

The RPM's are built from a Maven plugin and depend on 'rpmbuild'.

Yum handling and signing will be done later.
Linux installer improvements

Following some feedback from Anders:

* The Debian maintainer name is nicely generic
* The RPM licensing info is accurate
Merge pull request #1101 from simpsonjulian/rpm-package

Experimental RPM support and restructuring of installer-linux