Update our public documentation to use the Terraform solution instead of the bundle

[mvlassis]

Context

With the Terraform solution being prioritized as the main way of deploying Charmed Kubeflow, we should update our documentation to reflect the change. This also applies to deploying MLFlow and Feast as well.

What needs to get done

• Find all references in our documentation that deploy the Kubeflow or MLFlow bundles
• Replace the deploying part with using the Terraform solutions

Definition of Done

None of our documentation pages deploy Kubeflow/MLflow/Feast with the bundle