Hackday project: templates to generate new Terraform modules

Description

A hackday project to add some boilerplate templates to generate Terraform modules:

Template to generate a basic Terraform module that follows all of our conventions: file naming conventions (variables.tf, outputs.tf, etc), commenting conventions, provider versioning conventions, code formatting, etc.
Template to generate a basic Terraform module with examples and tests. The example uses the generated module and the automated test tests the example. Again, everything follows our conventions: test stages, namespacing with unique IDs, etc.
Template to generate a wrapper module of an existing module, along with examples and tests. This makes it easier to create/maintain wrapper modules like we have in the CIS Service Catalog.
Some fixes and improvements to boilerplate itself:
- Add support for setting a custom working directory for hooks using the dir param.
- Fix a bug in the parsing of --var KEY=VALUE flags where it would break if VALUE contained an equals sign.

[x] Update the docs.
[ ] Run the relevant tests successfully, including pre-commit checks.
[x] Ensure any 3rd party code adheres with our license policy or delete this line if its not applicable.
[x] Include release notes. If this PR is backward incompatible, include a migration guide.

Added / Removed / Updated [X].