Introduction of UI tests into the Configuration UI project

[mariusoe]

Currently, the Configuration UI project does not include or use any UI tests to detect bugs early and ensure that existing functionality is not broken in new developments. Therefore, a concept should be elaborated so that UI tests can be introduced and implemented in future tasks.

This ticket is not about implementing missing UI tests, but about selecting a suitable framework and creating the basis for future UI tests, e.g. with an exemplary implementation of individual tests and integration into the current CI pipeline.