Step 2 - Setup `useFakeDate` by default in Jest

• Step 1 - Add fake_date test helper
• Step 2 - Setup useFakeDate by default in Jest
• Step 3 - Update default fake date to match rspec fixtures
• Step 3 - Add helper for useFixturesFakeDate

What does this MR do?

This MR sets up useFakeDate by default in our Jest environment

spec/frontend/__helpers__/fake_date.js

-// Frida Kahlo's birthday (6 = July)
-export const DEFAULT_ARGS = [2020, 6, 6];
+// Date used in `spec/support/helpers/javascript_fixtures_helpers.rb`
+// Also Franz Kafka's Birthday (6 = July)
+export const DEFAULT_ARGS = [2015, 6, 3, 10];
 
 const RealDate = Date;