Installer: Merge fcos and master branches

As an OKD release engineer,
I want to build OKD off of the OCP release branches of all OpenShift components.

This includes the installer repository.

Currently the OKD installer is built off of the `fcos` branch in the installer repository and includes a couple of downstream changes:

• Azure image caching (required as no FCOS image is available on the Azure Marketplace)
• Different Operator Catalog manifest
• a different image manifest (`fcos.json` vs`rhcos.json` in OCP). This may possibly be resolvable when the installer switches to pull the image references from a container, instead of building them into the binary.

and possibly a few more.