Hide AKM menu and disable the qt connection.

Hide the Advaneced Key Management menu from the ui file and comment out
the connection between the triggered action and the method that shows
the AKM window.

Closes #6087.
Merge remote-tracking branch 'refs/remotes/ivan/feature/6087_remove-AKM-menu' into develop
Move eip preferences to new combined preference window.
enabled/disable services via preferences window, account page.
moved password change UI to a separate window, opened from account page in preferences.
single preference window gets the autopep8 beauty scrub.
vpn preferences: clean up error code & don't show dummy gateways in case of error.
move preference window tracking to PreferencesWindow
preferences window: minor linting