add support for autodownloading gof and files

[prabirshrestha]

Plug 'mattn/vim-fz', { 'do': ':FzInstallBin' }

[smekkley]

I'm against this. It is one of the reasons I'm not using vim fzf.
Binaries should be provided by the package managers. Afaik the plugins that use python, ripgrep, or clang don't install the binary through vim scripts.