Add support for Registration URL Certs for RMT

[mallardduck]

Per title, finish building support for registration URL certs for the RMT style registration use-case.

For QA

ORBS Team

The biggest concern is to test for regressions of known working use-cases that we cover.

Non-ORBS Team(s)

You can fully test Rancher (and SCC Operator) against RMT or which ever systems are needed.

[mallardduck]

Setting to blocked as we are waiting for the Cloud team to do some testing before merging the PR.