Add `reload` action alongside to the `visit` action

[wKich]

react-admin project uses cypress, which has reload method. But Page interactor of BigTest doesn't have such action.

https://github.com/marmelab/react-admin/blob/master/cypress/integration/auth.js#L43

[jnicklas]

We're moving this type of functionality into bigtest, and bigtest will have a visit function, so maybe it could have a reload function as well?