BUG-2254 Make runtime rpcs in config subsystem/netconf handle context-instance attribute with namespaces

Change-Id: I9ca4accdb10ba5a6b52ce9b8f7ad02a8cbe8743d
Signed-off-by: Maros Marsalek <mmarsale@cisco.com>
Merge "BUG-2254 Make runtime rpcs in config subsystem/netconf handle context-instance attribute with namespaces"