Use libby-download on Android

[hugues61]

Thank you for this great add-on. As other people, I'd like to be able to use it on android. I saw somewhere that you answered you do not have the skills to do that, I don't either. I tested it and I wanted to share a few things. I uploaded your add-on on my android Firefox (going to the add-on store website, and making sure to be in desktop view). I was able to run it perfectly, I even got a message that the file is downloading, except that the file is not downloading. It seems to me that the add-on works but there is probably something like a authorization issue that blocks the download... It seems that it's not missing much to make it work.
Once again, thank you for the great work :)))