User Signup

## Description
In this branch, a user with an email in the whitelist will be able create an account and login. Press tab to switch between login and signup. If errors occur, they will be in red and when information is shown, it will be shown in purple.

**Note: Email authentication is disabled**

### Testing Considerations
* [x] Ensure a user can signup and then get redirected to the dashboard
* [x] Ensure a user can login and get redirected to the dashboard
* [x] Ensure edited snippets are accounted for when logging in or signing up
* [x] Ensure deleted snippets reset the dialog to the appropriate place
* [x] Ensure error and info snippets are deleted after each new input
* [x] Ensure the hovering new snippet element is shown on note page
* [x] Ensure user can login with Chrome, Firefox, & Safari
* [x] Ensure a user can edit a snippet in Firefox
* [x] Ensure login box is vertically centered in Firefox