Release 3.3.0-rc2

• desktop#3488 Remove unused pushNotifications variable
• desktop#3498 Fix QML Warnings and create custom component for the activity list
• desktop#3541 Use dav instead of webdav
• desktop#3542 Enforce https in flow2 for https connections
• desktop#3548 Update screenshot in README.md
• desktop#3552 Remove request to config for userVisibleURL.
• desktop#3557 Fix size of the Label with user status
• desktop#3558 Bugfix/user status too long account menu
• desktop#3565 Do not block account menu: availability checking can be slow
• desktop#3566 Create QMessageBox on heap and continue running the app when update is ready.
• desktop#3569 Print the real permissions string instead of its address
• desktop#3574 Open main dialog gnome always