[TESTING] Cypress tests refactorization

[jpelay]

Description

The cypress tests can be improved further by making some changes:

• Using data-cy=* selectors instead of id and css classes.
• Remove waits (by removing waits in the login page I was able to shave off about 2 minutes of testing)
• Put the tests in a single file and use beforeEach instead of repeating the same line of code over and over again.
• Use ensureClass instead of createClass to not add hundreds of classes each time we run the tests.

Fixes #4027, fixes #4026

How to test

npx cypress run