0.6.0

• Add license files for source code and binary releases.
• Switch from PyQt5 to PySide2 to avoid licensing issues.
• Search for chromedriver in a more platform-independent path.
• Fix correctly searching for modules directory independently of where the main script is called from.
• Check chromedriver availability and show a warning if it's missing instead of silently failing.
• Make ICU optional because it's not supported in Windows.
• Force QWizard Classic style because Aero looks so bad in Windows.
• Use QSettings abstraction to store application settings instead of plaintext files.
• Use keyring abstraction to store credentials securely instead of plaintext files.
• Remove external dependencies loaded dynamically in Windows and MacOS binary builds.
• Add support for Python 3.9.
• Add support for Windows and MacOS binary releases.
• Improve code styling and best practices (PEP8, marking Qt slots and not accessing UI elements from threads).
• Don't use XDG icons for sync results because they are usually not available in Windows and MacOS.
• Fix allowing to progress to step 2 when step 1 is still not completed.
• Add binary releases and installer for Windows and MacOS.