support for being consumed as a library

[kbirger]

This package is great, and it has potential for being used as a part of larger tools. It would be useful in my opinion to create a proper interface for being imported into another JS/TS module.

You are already more or less able to do this by requiring gherkin-lint/dist/linter (etc), but it would be helpful to have a first-party interface to use, and potentially the ability to consume a file's contents as opposed to a path.

On this subject, I'd also be happy to contribute to these and other efforts on this project