Update the SaaS deployment process to use the refactored `config` commands

[mrsimonemms]

As part of the parent task, the Installer's configuration commands have updated. These will need to be incorporated into the SaaS process for building the YAML files for deployment to our clusters.

• The init command is now deprecated in favour of config init Create a config command #12678
• There are detection commands for the ShiftFS status and containerd location (this may not be needed) Create a config cluster shiftfs and config files containerd command in the Installer that will do the detection of shiftfs support/containerd location #12198
• There is a new config build-from-envvars command to build the config parameters (this may not be needed) create a config build-from-envvars command in the Installer that will build the config.yaml from envvars #12199

[mads-hartmann]

The init command isn't used as pat of SaaS deployments. We only use the render command - see here and here ☺️ The config files are checked into git, e.g. here