Add skip navigation button

[andrico1234]

Notes

I messed up the rebase, and I'm just opening up a new PR with the same changes.

Description

I've added a button inside of Layout.tsx that only displays when the first action a user performs on a RA site is pressing the tab button.

This moves the focus into the main content of the website, avoiding having to tab through the top and side menus.

While the functionality is complete, I'm going to write Cypress tests for this functionality.

Notes:

Because navigating to anchors via the # didn't seem to work nicely with HashRouter, I had to install an node module that exports a custom link. Here's a link to the discussion

Fortunately the module has no dependencies, and it works out of the box.

I implementing this component similarly to how it's written inside of the Material-UI repo. You can view their implementation here

skip-navigation-smol.mov

[andrico1234]

This is no longer a WIP, I believe the code is exactly how the previous MR was before I messed up the. rebase

[djhi]

Thanks!

[fzaninotto]

Thanks a lot, this is a great feature!