NEW: cloudinit tested in OpenNebula 4.6.1 (rocci client 4.2.5) and Openstack Grizzly (nova client 2.15.0)

After some testing this PR is collecting different BUGFIXes from v1r0pre and a big NEW feature cloudinit
the merging is a NEW featured + further stable release (v1r1)
cloudinit is (after many months awaiting) a common contextualization method for different cloudmanagers and most of Images it is recomended in terms of image management and federated cloud compexity, with cloudinti VMDIRAC is able to implement a complete automate common contextualization for different cloud mangers
Supported cloudmangers for cloudinit with DIRAC should be at least:
OpenNebula 4.6.1 (rocci client 4.2.5)
Openstack Grizzly (nova client 2.15.0)

Note about available contextualization templates and scripts at WorkloadManagement/private/bootstrap:
Every user should copy the most convenient scripts and create their onws DO NOT MODIFIED THE AVAILABLES, PR updateing those scritps would not be accepted
Available templates and scripts are designed to work with regular golden images including cloudinit utilities (tested in SL 6 and Ubuntu 13)
CernVM 3: CernVM 3 has a major impediment for elastic clouds: it has a two phases booting sequences:
1) a Minimal image boot loader  is preparing the root filesystem with cernvmfs
2) the root filesystem is booted, cernvmfs is downloading only the necessary files to such booting (about 200Mb) the rest of the files would be uploaded only when required by user.
Inconvenient: Such 200Mb downlaoded take about 20-30 min to download in a standar cloud manager, which is incompatible with elastic cloud
Possible tested solution: To install in each hypervisor a squid proxy and iptables redirections in order to increase booting time after the first image files download. To connect these local squids with the site squid.
Conclusion: Since this problem is not resolved CernVM is not recommended for elastic clouds
DIRAC is not providing contextualization scripts for this 2 phases cloudinit-cernvm way