command-not-found to support NIX_AUTO_RUN_INTERACTIVE

[evysgarden]

there's currently no handling for NIX_AUTO_RUN_INTERACTIVE.
it would be nice to be prompted to run a command with nix-shell if it's not installed.

furthermore it could present a selection when several packages provide the same command.

[evysgarden]

Something like this would be nice

$ export NIX_AUTO_RUN_INTERACTIVE=1
$ chromium
The program 'chromium' is currently not installed. It is provided by
several packages.
1. ungoogled-chromium.out
2. chromium.out
Should the first output be used?
([Y]es | [number] | [n]one): 2
/nix/store/aaaaaaaaaaaaaaaaaaaaaaa-chromium-0.0.0