Run the output through terraform fmt

[jrhouston]

Right now the output doesn't get format, so attributes don't get aligned and so on. We should programatically run terraform fmt so that the tfk8s output doesn't need to be formatted.

[jrhouston]

The logic behind terraform fmt is internal, and looks like a significant amount of code to have to copy over 😓 https://github.com/hashicorp/terraform/blob/7d3074df46b3d3351424a3b44df590fdcbbc6aad/internal/command/fmt.go#L271

terraform fmt does however support reading from STDIN, so we could use terraform-exec which supports the fmt feature. This requires tfk8s to find or download the terraform binary which kind of sucks, though.