Support for overwritting packages

[RedsonBr140]

Let me explain: We need to install for example neofetch

 Repository                     Stars   IsFork
 ----------                     -----   ------
 [0] dylanaraps/neofetch        15601   no
 [1] ss7m/paleofetch            133     no
 [2] Chick2D/neofetch-themes    173     no
 [3] denisse-dev/dotfiles       928     no
 [4] K4rakara/freshfetch        260     no

Then we select 0, the original neofetch, and fpkg says something like: :: This package has a version modified by the fpkg maintainers. Install [y/N]

And we have a FpkgProject/neofetch, that's a fork of dylanaraps/neofetch.