Introduce role::ganglia classes

Introducing role classes for ganglia, based on the ganglia_new module
which also gets some new functionality. For now the role::ganglia::web
exists only but more stuff needs to be migrated in the future.

Update ganglia_new module to support:
* gmetad configuration
* rrdcached
* Override the default gmetad upstart script for RRDCACHED support
* gmetad configuration in the role
* Some preliminary tests support
* ganglia web frontend configuration

Change-Id: Iedd12f64b8a733c8c9c7df706d1c33397754cc37
Merge "Introduce role::ganglia classes" into production