lint: add new lint to check that all modules are used in the main module

[Dentrax]

Description

To ensure image module is instantiated in the root main.tf.

• [ ] migrate the lint.sh code to wolfictl

As we discussed with @imjasonh, dropping the idea here so we don't forget.

[imjasonh]

We did something simple with a shell script for now: https://github.com/chainguard-images/images/pull/1014