Switch from Turtles to embedded CAPI

[salasberryfin]

Description

As a user on rancher:v2.13.x, I'd like to enable embedded-cluster-api back and disable Turtles.

Definition of Done

A new test validates that, after installing rancher:v2.13.x, Turtles becomes the only source of truth for CAPI CRDs and controllers. Eventually, this configuration is changed and embedded-cluster-api feature is enabled. Existing clusters and provisioning should be unaffected.

Ideally we should also check that users can go back Turtles once again.

[valaparthvi]

I would like to work on this if no one else has picked it up. I am assigning it to myself for now.