ZITADEL New Login UI: Standardize the way of writing and running acceptance tests.

[eliobischof]

As a developer, I want to have an easy way to run acceptance tests, so that I can easily maintain them.

Acceptance Criteria

• [x] An example acceptance test is easily runnable locally.
• [x] Changes are just merged to main, if all acceptance tests succeed.
• [x] The PR Template lists the following ready for review checks:
  • Acceptance tests ensure that all probable local login and registration flows work as expected (The ZITADEL API is not mocked).
  • Acceptance tests ensure that all probable external login and registration flows work as expected (IDPs are mocked but the ZITADEL API isn’t).

[adlerhurst]

reevaluate cypress

setup structure