Improve docs

[Ygg01]

This is more of a meta issue, so contributors can expand docs and add it.

What docs are needed?

• API Docs. Easiest to add needed on most public methods
• How-To. Just a quick cookbook examples how to setup some Linguini in a specific case. No external dependencies needed.
• Tutorial??. Possibly needed, but Linguini is relatively simple.
• Onboarding docs for new contributors?? Not sure what people need.