This replaces a custom token-based substitution format with calls to
Spec.format in modules.py
This also resolves a couple issues:
- LmodModules set configuration globally instead of in its initializer
which meant test-specific configuration was not applied
- Added support for setting hash_length=0 for LmodModules. This only
affects the module filename and not the directory names for the
hierarchy tokens in the path. This includes an additional unit test.
23683c65de