[Suggestion] Replace terraform with opentofu

[Moortu]

Terraform is going into the commercial business. Opentofu is the opensource fork from terraform and should be a simple dropin replacement.

[kvendingoldo]

you can also you https://github.com/tofuutils/tenv to switch between different versions of terraform/tofu

[khuedoan]

Thanks, I'll replace Terraform with OpenTofu in the upcoming commits. I've been using it in some other projects as well (this will require some changes to ./external and the prerequisites instructions though)