"Add, update, or remove UGENE components" item and "Help" menu restructure

Modify the main "Help" menu in UGENE. For online packages (on Windows, macOS and Linux) it should look as follows:

• Open UGENE user manual
• View UGENE documentation online
• Visit UGENE web site
• ---------------------------
• Check for updates...
• Add, update, or remove UGENE components...
• ---------------------------
• Open Start Page

For offline packages (on Windows, macOS and Linux) it should be:

• Open UGENE user manual
• View UGENE documentation online
• Visit UGENE web site
• ---------------------------
• Check for updates...
• ---------------------------
• Open Start Page

In an online package when the "Add, update, or remove UGENE components" item is clicked, a message box should appear with title "Confirm UGENE Closing" and message:

To add, update, or remove UGENE components it is required to run the installation wizard. UGENE will be closed automatically.

The message box should have buttons "Help", "OK", and "Cancel" in the standard layout.

If "OK" is selected, UGENE is attempting to close. A user may need to confirm that some tasks should be stopped or files should be saved. In case a user doesn't stop tasks, the closing is canceled.

After UGENE is closed, "setup" executable file is launched and "Maintain Unipro UGENE Installer" wizard is shown.