Support automatic update of UGENE modules

The feature description:

1. Every certain time period (e.g. 30 minutes) UGENE checks for updates on the UGENE server. Also it is checked when UGENE starts.
2. If there are new updates, UGENE waits while all modal dialogs are closed and then asks: "UGENE has new updates. Would you like to download and install them?". There are 3 possible answers:
   • Ask later. The question will appear again in that time period or on the next UGENE start.
   • Don't install this update. The question won't appear until new UGENE updates are released.
   • Download now. The updates are downloading like a usual UGENE task (it can be canceled).
3. All data is downloaded to a temporary directory.
4. UGENE downloads only new packages (with new versions), but not all.
5. UGENE updates only packages that are installed, but not all.
6. When the downloading is finished a new question appears: "The new update updates are ready to install. Would you like to restart UGENE now and install the updates?". There are two possible answers:
   • Install now.
   • Install on the next UGENE start.
7. After restart UGENE runs a special executable file that unpacks the downloaded data, showing the progress, and starts updated UGENE.
8. After installing, the temporary files are removed from the download directory.
9. When updated UGENE start for the first time, it shows the what's new information.
10. The dialog Help -> Check for Updated must be changed. If there are new updates available, then it should offer to download them now.

There are new settings:

1. A checkbox "Install automatic updates" in the General tab. If it is switched off then the updates are not checked.
2. A directory for temporary downloaded files. ".UGENE_downloaded" can be reused.