Update AdAdawy hosts issue report link

Update AdAdawy hosts issue report link

Hi @StevenBlack

I hope you're going well.
I propose a small change about the link to report an issue about AdAway's default hosts. I link it to the site GitHub project, not the application.
Moreover, @jawz101 has taken over the `hosts` file management. There is [more frequent updates](https://github.com/AdAway/adaway.github.io/commits/master) than ever so you might also want to change the _occasionnaly_ frequence label.

I take the opportunity of this PR to announce your hosts will be integrated as default source for the AdAway application! 🎉
I think some of the users already added it to their configuration but it will be enabled by default for all new users.
I hope it is fine to you. Don't hesitate to tell me if not.

Regards