Fix multiple issues in offsets extractor

[laxa]

This PR fix multiple issues in the extractor:

• A crash in the version check of radare2 depending on the release taken
• The progress not showing correctly when downloading and processing files. I had to remove some verbose information to avoid the progress being rewritten
• Introducing locks when downloading files to prevent any race when printing
• Now finding version information in the nested json file to prevent some crashes and potentially retrieving more ntoskrnl.exe files

[themaks]

Hey ! Thanks for the contributions and the fixes! ("better late than never", but I'm really sorry for the delay ^^)

I took the liberty to edit your commits ; regarding "A crash in the version check of radare2 depending on the release taken", I already pushed a fix between the time of your PR and today, that seems to cover an additional format of radare2 version tag. If you have a test case that crash the current code, don't hesitate to share it in the code comment (see here) and fix the code if necessary Thanks for the rest!

PS : I failed to push the edited commits back inside this PR, somehow, they are in new commmit on master, see a561976b5dd700de6d0453a82715390c08e5f501 and 45d3ff5486ae795d362af5c9478b4467085bfc71