feature/traverse: Add an option to rely purely on ignore files for traversing directories

[MA-DDN]

What does this PR accomplish?

• 🦚 Feature

Changes proposed by this PR:

This pr adds an option flag to change the behaviour of the traversal module to collect all relevant files except those which match an entry in a .gitignore file. Our usecase for this is to be able to ignore certain temporary Markdown files which are pulled in when building our documentation.

📜 Checklist

• [x] Works on the ./demo sub directory
• [x] Test coverage is excellent and passes
• [x] Documentation is thorough

[drahnr]

Gentle ping @MA-DDN

[jgrund]

Looks like this was updated. Could it be re-reviewed?

[drahnr]

I'll get to it next week