Adds a .tfswitch.toml to each module to select the appropriate tf version
Is this a good idea?
Since we don't have a `version.tf`, nothing is telling `tfswitch` which
version we want to use, so when we run it, it prompts to ask. Adding this
`.tfswitch.toml` file to each directory tells tfsiwtch which version to
use.
lmk what you think. You do NOT need to rubber stamp this.