Dockerfiles don't work, and are installing terraform via tfenv

[jrdemasi]

Would you accept a PR updating all the Dockerfiles to use opentofu 1.6 or terraform 1.5.5 (based on an env var or default, maybe)? Additionally, I can fix the failing gem installs which people have pointed out in the terraspace repo.

Point of clarification: The Dockerfiles work, but occasionally present an error related to the terraspace_aws_plugin that might be concerning for new users or people who aren't otherwise expecting it. The CentOS container in particular has no repos due to CentOS EOL issues or something else.

[kvendingoldo]

btw. try to use tenv to manage your Terraform/OpenTofu installation