ci: add e2e tests with cypress

* Creates E2E tests using Cypress and includes two tests

* Improves yarn.lock file

* Includes documentation

* Cypress project id

* test e2e w/ ci and video

* run unit command before e2e

* Also cache cypress

* Persist cypress to next build step

* Try a different path

* Try without working dir

* Persist less data, but restore yarn/cypress cache in next step

* Install cypress to invalidate cache

* Add e2e as a blocker for merged publishing

cypress/support/commands.js

@@ -0,0 +1,25 @@
+// ***********************************************
+// This example commands.js shows you how to
+// create various custom commands and overwrite
+// existing commands.
+//
+// For more comprehensive examples of custom
+// commands please read more here:
+// https://on.cypress.io/custom-commands
+// ***********************************************
+//
+//
+// -- This is a parent command --
+// Cypress.Commands.add("login", (email, password) => { ... })
+//
+//
+// -- This is a child command --
+// Cypress.Commands.add("drag", { prevSubject: 'element'}, (subject, options) => { ... })
+//
+//
+// -- This is a dual command --
+// Cypress.Commands.add("dismiss", { prevSubject: 'optional'}, (subject, options) => { ... })
+//
+//
+// -- This is will overwrite an existing command --
+// Cypress.Commands.overwrite("visit", (originalFn, url, options) => { ... })