hub: separate internal features from the rest of the code base

[lzaoral]

Since ET integration and Coverity statistics are practically useless outside of the internal deployment, let's separate them from the rest of the code base.

[kdudka]

What does Coverity statistics mean in the context of this git repository?

[lzaoral]

Some statistics are dependent on values provided by Coverity. On the other hand, the whole stats Django app is useless without ET so that could be separated as well.

@siteshwar Do you plan to use the stats Django app in Fedora?

[siteshwar]

@siteshwar Do you plan to use the stats Django app in Fedora?

I have no plans to use it.