get_node_details function only using CFS sessions (and not BOS sessiontemplate) to fetch the configuration used to build boot image

[Masber]

get_node_details function shows the CFS configuration used to build the node's boot image, at the moment this information is taken from CFS configuration details linked to target (HSM group or xname) related to the node.
This task is to add BOS sessiontemplate details to find the CFS session used to build the image. This is needed if CFS sessions gets deleted