Support for node image management

[mapuri]

until now clusterm manages the configuration of the cluster nodes. One of the items in clusterm's charter has been the ability to manage images for the nodes to further automate the process to onboard a node in the cluster.

Ideally the node image management feature shall address:

• image distribution
• image installation
• image upgrades

The design shall use off the shelf tools and standard workflows to achieve the same as much as possible.

This issue tracks this requirement. Ideas/Contributions are welcome.