Guide for migrating from Terraform to Crossplane Providers

### What problem are you facing?

Crossplane is able to provision infrastructure through infra-stacks and schedule applications through app-stacks (or directly via workload scheduler).

The users who decide to go with Crossplane have a number of different setups and AFAIK the combination of Terraform and Helm is one of the most popular ones. For Helm, we have the template stacks work going on which would allow a helm chart to be used directly. However, users do not have a guide/script for migrating from Terraform to Crossplane infra stacks.

### How could Crossplane help solve your problem?

A guide that explains how Terraform setups could be migrated with examples could be useful for users to easily migrate as well as see what their setup would look like before deciding.