In order to fix the flakiness in cockpit plugin tests introduced by the single login, the tests need a check if they are authenticated at the start of their execution and relog in case the session expired.
Add a single login for all tests in the form of a global setup. This commit also removes the login from all tests and replaces it with navigation to landing page and revamps the popup closing logic from being applied in logging step into a separate fixture.
Adds a Hostname customization test that creates a BP, edits BP, exports and imports it back and verifies the BP content.
This test also servers as a template for other customization tests. Includes a refactor of existing helper functions.
