vim: variants conflict with each other

[BKPepe]

Maintainer: @ratkaj Compile tested: N/A Run tested: N/A

Description:

This adds conflicts between the variants, because they provide the same files, and it should not be possible to install them side by side. Otherwise, it might happen that half files would be from one variant and the other half from the other.

Also, adds provides as if you request to install vim and vim-full, then the request could be satisfied even they collide, because vim-full provides vim package.

Fixes: https://forum.turris.cz/t/installing-vim-fuller-breaks-automatic-updates/16720