Support simple automatic update of UGENE modules

The feature description:

1. When UGENE starts it checks for updates on the UGENE server.
2. If there are new updates, UGENE waits while all modal dialogs are closed and then asks:

   UGENE %1 is available for downloading. Would you like to download and install it?

   There are 3 possible answers:

   • Ask later. The question will appear again on the next UGENE start.
   • Skip this update. The question won't appear until new UGENE updates are released.
   • Update now.
     • For UGENE with maintenance tool: UGENE is closed and the online installer (Qt Installer maintenance tool) starts.
     • For UGENE installed from Fedora or Ubuntu repositories: a UGENE web site is opened with a web browser.
3. There are check boxes in the installer for modules. If a module is installed its check box is checked. And it is unchecked if the module is not installed.
4. Users can add or remove modules during the update.
5. The dialog Help -> Check for Updates must be changed. If there are new updates available, then it should offer to install them now.

There is a new settings: a check box "Install automatic updates" in the General tab. If it is switched off then the updates are not checked automatically.