Gherkin cypress spike (#673)

* integrate gherkin/cucumber w/ cypress

- change cypress.json config from e2e back to standard integration
- add cypress-cucumber-preprocessor
- add integration test of about page

* add a title to each page

* add intl to the 404 page

* Refactor explore tool page

- add intl to static strings
- replace component css with <Grid> layout

* Add title to contact page

* add intl to title of page

* Add gherkin tests for nav to about page

- navigate from any page to the about page
- ensure each link has the title correct on that page

client/cypress/integration/LegacyTests/downloadPacket.spec.js

@@ -0,0 +1,22 @@
+// / <reference types="Cypress" />
+
+describe('Census Block Group packet download', () => {
+  const filename = `Screening_Tool_Data.zip`;
+  it('validate file download', () => {
+    cy.visit('localhost:8000/en/methodology');
+
+    cy.get('[data-cy="download-link"]').invoke('attr', 'target', '_blank');
+    cy.intercept(`https://d3jqyw10j8e7p9.cloudfront.net/data-pipeline/data/score/downloadable/${filename}`,
+        {
+          body: 'success',
+          headers: {
+            'Content-Type': 'text/html; charset=utf-8',
+            'Content-Disposition': 'attachment',
+          },
+        },
+    ).as('downloadRequest');
+    cy.get('button[class*="downloadPacket"]').click();
+    cy.wait('@downloadRequest');
+    cy.readFile(`cypress/downloads/${filename}`).should('exist');
+  });
+});