Public Engagement Page (#1372)

* Add public engagement page

- modifies sitemap config
- creates PublicEvent component
- adds SVGs for dates
- all copy is in intl

* Add Public Engagement button to each page

- create new PublicEng component
- add to each page
- update snapshots
- modify CEJST and Meth page to give button more space

* Make mobile compliant and fix DOM validation error

- transform each <p>'s descendent into a <CollectionDescription>
- fix a mobile rendering issue with <Collection> library
- format registration links so they render on mobile
- update snapshots

* Add spacing to descriptions and fix links

* Add Gherkin tests for testing links

- all zoom links should be functional
- ensure all legacy tests, test the new page
- add data-cy tag for cypress
- update snapshots

* Refactor to pass accessibility on all pages

- update snapshots

* Correct registration links

* Make registration links into buttons

* Make new tag bold

* Update copy based on feedback from Corey

client/gatsby-config.js

@@ -87,6 +87,7 @@ module.exports = {
           '/contact',
           '/methodology',
           '/404',
+          'public-engagement',
         ],
       },
     },