0.5.1 - Fix bugs related to root boundary

[emdoyle]

This fixes issues with using the implicit '' boundary in tach.yml.

Specifically:

• the root boundary causes tach to fail to build a module tree
• root boundary dependencies were being ignored

Also:

• report an error if modules are defined multiple times in tach.yml
• disabling pyright on VSCode extension for now due to virtualenv issues (separate set of dependencies causing import resolution errors)
• removing __init__.py files from tach mod since they do not represent standalone module paths