Red hat repositories is too slow
Cloned from https://bugzilla.redhat.com/show_bug.cgi?id=1405571
Description of problem:
Both listing repos and clicking on each repo is a very slow operation. From what I saw, it asks for all available data in candlepin about each product/subscription.
This is incredibly big to parse and to transfer at times. Candlepin provides an API to request only the necessary fields. Therefore we should use that.
Steps to Reproduce:
1. Go to red hat repositories
2. Wait a lot of time even if you have few repos. See the calls to candlepin API requesting all available info
3. Click on any repo. Wait a lot of time for that info.
It should just request the necessary data which would make the loading time much faster.
Fixes #17718 - Improve speed when clicking on RH repos
This commits improves the speed for both listing and clicking on
repositories on the Red Hat Repositories page. It does that by asking
the Candlepin API for just enough information to do every operation,
versus the current approach of fetching everything