Provide Constant Access to GDPR

[TaiWilkin]

Overview

Allows users to click a link in the footer (on web) or in the dropdown
menu (on mobile) to open the GDPR notification, at which point they
can choose to accept or reject cookies, clearing their previous
selection.

Connects #1261

Demo

Testing Instructions

• Run ./scripts/server and navigate to localhost:6543/
• Clear your local storage and refresh the page
  • You should see the GDPR notification
• Select Accept or Reject
  • Your preference should be updated in local storage appropriately
• Click on 'Cookie Preferences' in the footer
  • You should see the GDPR notification
• Select Accept or Reject
  • Your preference should be updated in local storage appropriately
• Make the viewport narrow to simulate mobile and click the Menu button
  • You should see a 'Cookie Preferences' button
• Click on the 'Cookie Preferences' menu item
  • You should see the GDPR notification
• Select Accept or Reject
  • Your preference should be updated in local storage appropriately

Checklist

• fixup! commits have been squashed
• CI passes after rebase
• CHANGELOG.md updated with summary of features or fixes, following Keep a Changelog guidelines

[jwalgran]

Works perfectly. Nice, unobtrusive design.