Display appropriate message when user does not have some privilege

[antonsviridenko]

When user does not have "remote client access" privilege, server is marked by red circle and error message from server "You do not have permission to use remote client" is printed on stdout. But this message does not appear in GUI.

When user does not have "Backup access (recorded video)", message

EventData::parseEvents error: "Invalid feed format"

is printed on stdout and no events appear in event view windows.

Error message for "Backup access" privilege is not implemented on server side.