[poky] Qt commercial support

[Felipe Ferreri Tonello]

Basically there is still no easy way to support commercial Qt versions. 
Yocto Bug #2505 fixes part of it but not all.

In my case I have to provide, not just a qt4-x11-commercial recipe, but 
all others native and sdk recipes basically because the OE-Core ones 
enforces the download of the opensource version.

It would be perfect if we can provide our own .tar.gz or git repo with 
our modified Qt version.

I know that we can provide a bbappend to change that but still not a 
perfect solution.

Is there a better way to fix that? Maybe a patch idea.

Regards

Felipe Tonello