e2e test register

[emilyparkes]

This ticket has a difficulty warning.

e2e are end to end tests:

These are written to mock how a user would interact with the product and ensure it behaves as it should.

Auth register needs to be implemented in the dev branch before this test can be written.

Cypress is new and has not been taught so this task may be a steep exercise.

References:
reka by Don
cypress docs