OSPF module adds loopback interface, while ISIS leaves it up to the templates

[jbemmel]

For example:
ISIS:

netlab/netsim/ansible/templates/isis/eos.j2

Line 8 in 5b580c0

isis enable {{ isis.instance }}

OSPF:

netlab/netsim/modules/ospf.py

Line 65 in 5b580c0

node.loopback.ospf.area = node.ospf.area

It will work and it's not a big deal - but for consistency it might be better to have the ISIS module replicate what is done for OSPF

[ipspace]

Moved to #1937