flake.nix: remove unnecessary build inputs

Dependencies

• [2] G734WNM6 flake.nix: use crate2nix
• [3] SXEYMYF7 Fixing the bad changes in history (unfortunately, by rebooting).

Change contents

• edit in flake.nix at line 70
  [2.246504]

  [2.246504]
  + openssl
• edit in flake.nix at line 96
  [2.247036]→[2.247036:247102](∅→∅)
  − libsodium

  − openssl