[Pytest] PyTest integration

[squ1sher]

• Integrate squish and pytest
• Prepare structure for "squish driver"
• Implement managing squishserver during a test
• Implement setup, start, and stop the application with custom user data
• Prepare the Main Window fixture
• Add test on "Backup seed phrase"
• Implement Attach mode
• Setup parallel execution via Virtual Box
• Setup pipeline