Update certmanager to versison 0.4.x

We are on certmanager 0.2.4, and in certmanager 0.3, support for acmev2 and some work on wildcard certs was added.

Unfortunately the upgrade from 0.2 to 0.3 included breaking changes that need to be manually applied. Meaning I think we should try and get this upgrade in for our GA.

The breaking changes are documented here: https://cert-manager.readthedocs.io/en/release-0.4/admin/upgrading/upgrading-0.2-0.3.html

The two that require manual work for our users are the moving the resources out of kube-system, and the requirement to scale certmanager to 0 before doing the upgrade.

Possibly we could consider a pre-hook job to do these actions for the user, otherwise we will need to have them do it manually.