Replace APK URL to GitHub releases page with URL to our repo

[TobiGr]

Now, that we have our own F-Droid repository, we should change the download URL from GitHub/aws to our server.
@TheAssassin Is that ok for you or are you worried about the traffic?

[TheAssassin]

I doubt you'll ever manage to exceed my traffic limit. That should't be an issue at all. I'll be monitoring the situation.

We could always migrate to another system, too. Those APKs don't require too much space on disk.

[B0pol]

Wouldn't it be better to add a new flavor? I don't see why we would remove GitHub option.

[TheAssassin]

It's the exactly same binary, however, from our server, people aren't exposed to tracking by GitHub.

[B0pol]

I know. But what if newpipe.net is down? Why would you not keep it as fallback?

[TheAssassin]

If newpipe.net is down, the website is down, too. They're hosted on the same system.