use single-consumer call when regenerating applicability
In http://projects.theforeman.org/issues/19055, a new API call is exposed to Pulp which allows applicability regen to not pin to a particular worker.
If only one consumer UUID is being updated, Katello should use this call instead of the multi-UUID call.
Fixes #19076 - use new runcible call for applicability
The previous consumer regen call would 'pin' to a single worker0.
Instead, use an API call to Pulp that can be spread across multiple
workers. Note that this requires
https://github.com/Katello/runcible/pull/189 to work.
I had to rename `name` to `consumer_name` to work around a tricky
issue. There was an interaction between minitest and VCR where it
would see a var named `name` in a test class, get confused, and pass
all the tests.