Preparation for GitHub user login

[smith]

• Add authorization for some pages that redirects to sign in page when not
  signed in
• Show/hide side bar items based on whether or not you're signed in
• Remove the HomeComponent and just have / redirect to /pkgs
• Add a reset middleware that resets the entire app state when signing
  out
• Make the usernav component take parameters instead of relying on the
  AppStore
• Put the current user info at users.current instead of user in the
  state
• Get rid of the sign up form and only use the sign in form

[chef-delivery]

This PR has passed 'Verify' and is ready for review and approval!
Use: '@delivery approve' when code review is complete.

[reset]

@smith solid work man, looks good!

@delivery approve

[chef-delivery]

Change: 7e9e6718-810b-4b5b-8e94-f881e9f21775 approved by: @reset