Allow default sandbox paths to be overriden
Allow default sandbox paths to be overriden

E.g. you can now redirect /etc/resolv.conf to a different file.

NixOS/nix,ehmry/nix,zimbatm/nix,rycee/nix,rycee/nix,layus/nix,ehmry/nix,ehmry/nix,peti/nix,bennofs/nix,rycee/nix,NixOS/nix,dtzWill/nix,NixOS/nix,dezgeg/nix,pikajude/nix,vcunat/nix,bennofs/nix,layus/nix,shlevy/nix,dtzWill/nix,pikajude/nix,rycee/nix,shlevy/nix,rycee/nix,vcunat/nix,dezgeg/nix,bennofs/nix,zimbatm/nix,shlevy/nix,vcunat/nix,peti/nix,zimbatm/nix,ehmry/nix,vcunat/nix,shlevy/nix,shlevy/nix,layus/nix,ehmry/nix,peti/nix,dtzWill/nix,bennofs/nix,ehmry/nix,dtzWill/nix,dezgeg/nix,NixOS/nix,dezgeg/nix,layus/nix,pikajude/nix,zimbatm/nix,peti/nix,NixOS/nix,layus/nix,dtzWill/nix,peti/nix,dezgeg/nix