Overwrite hostname reported by ganglia

User ganglia's overwrite_hostname to force the VM hostname. Avoids VMs
on private networks to appear as their gateway in the ganglia monitoring
interface. Requires ganglia puppet module at commit
MadMalcolm/puppet-ganglia@7e0c34f6e5397f5b49e01a832ac3741c90c13c2a.
Added group ssh keys for debugging access.

Changes:
	modified:   manifests/site.pp
	modified:   modules/gce_node/manifests/init.pp
Add type to ssh key entries

Fix ssh key insertion by adding encryption type to each puppet entry.

Changes:
	modified:   manifests/site.pp
Remove operatingsystemmajorrelease from puppet

Ensure modules work with CernVM by removing operatingsystemmajorrelease
fact. Wait for puppet and facter to be updated on CernVM.

Changes:
	modified:   modules/packagerepos/manifests/yumrepos.pp
Insert missing \ which broke one of the yum repos

Changes:
	modified:   modules/packagerepos/manifests/yumrepos.pp
Isolate ATLAS Specific configuration for use with environments

Isolate ATLAS production setup for use in puppet environments. Remove
Belle II configuration. Keep ssh keys for personnel needs access to
workers for debugging.

Changes:
	modified:   manifests/site.pp