Add workflow for adding capability sets

[shreyb]

With a transition at Fermilab from users using x509 proxies to SciTokens, we're seeing a lot of cases where we need to add a new capability set.

We should create a workflow that executes this set of steps:

https://github.com/DUNE/data-mgmt-ops/wiki/Dune-Physicsgroups-disk--how-to-create-a-new-physics-group

Starting at the step "Create the group in FERRY"

[shreyb]

I actually have a use case for this I'm going through right now, so I took the ticket.

[shreyb]

Almost done. Need to fix the last verification step.