Make `nix search` be able to use search.nixos.org 's cache

## Is your feature request related to a problem? <!-- A clear and concise description of what the problem is. Ex. I'm always frustrated when [...] --> `nix search` can take a long time to complete, while its work is constantly updated on NixOS Search - Packages https://search.nixos.org/ / https://github.com/nixos/nixos-search ; making it one of the reason users might go directly on https://search.nixos.org/ and not use this command at all ## Proposed solution <!-- A clear and concise description of what you want to happen. --> Make `nix search` be able to use search.nixos.org 's cache ## Additional context <!-- Add any other context or screenshots about the feature request here. --> Related : - [ ] #8603 ## Checklist <!-- make sure this issue is not redundant or obsolete --> - [x] checked [latest Nix manual] \([source]) - [x] checked [open feature issues and pull requests] for possible duplicates [latest Nix manual]: https://nix.dev/manual/nix/development/ [source]: https://github.com/NixOS/nix/tree/master/doc/manual/source [open feature issues and pull requests]: https://github.com/NixOS/nix/labels/feature --- Add :+1: to [issues you find important](https://github.com/NixOS/nix/issues?q=is%3Aissue+is%3Aopen+sort%3Areactions-%2B1-desc).