Move /docs to /documentation

[connormullett]

Summary of changes
Changes introduced in this pull request:

• removes redundancy between the two documentation folders

Reference issue to close (if applicable)

Closes #1386

Other information and links

[lemmih]

Remember to update the link to CONTRIBUTING.md in the README. (It used to be broken, let's fix it.)

[q9f]

Would be great to get this in before I tag the release 👆🏼

[connormullett]

Remember to update the link to CONTRIBUTING.md in the README. (It used to be broken, let's fix it.)

good catch, fixed.