Refactor Nav Props - See #824

[meiamsome]

I have verified that this pull request:

• has no linting errors (npm run lint)
• is from a uniquely-named feature branch and has been rebased on top of the latest master. (If I was asked to make more changes, I have made sure to rebase onto master then too)
• is descriptively named and links to an issue number, i.e. Fixes #123

Noting that I'm not using Fixes, so that the issue can be worked on over multiple PRs.

I think it makes sense to PR these refactors individually because the diffs will become quite unclear and big fairly quickly, so here is one refactoring. Let me know if you'd prefer me to do a bunch of them in one PR and I'll do that.

[catarak]

i definitely prefer smaller PR's, so keep doing the small ones!

i think this refactoring will also help with breaking up some of the components—a few of them are very large 😄

[catarak]

tested all of the nav functionality and it's working for me!