Basic tests with pytest-qt

[MihaMi27]

Added some basic tests for GUI as per issue #8.

To implement these tests, I needed to:

• fix the workflow file to allow GUI testing, see pytest-qt documentation,
• set sport-activities-features max version, as the current version 0.5.0 is not backwards compatible,
• add a new class CustomTCPServer and modify the CustomHandler class to toggle logging (the automated tests do not need HTTP access logs, it ruins the pytest output),
• add a new variable for specifying the port on which the HTTP server runs (each test generates its own server port to avoid "address already in use" issues,
• add default values to keep compatibility,
• add some basic STATIC tests (does not test simulated or real-time data, only data that is read from files)