Nix cataloger should use find by glob instead of iterating over all files

Catalogers should not iterate over each file and match a glob, but rather use a find by glob. See: https://github.com/anchore/syft/blob/main/syft/pkg/cataloger/nix/cataloger.go#L37-L38

Start in syft/pkg/cataloger/nix/cataloger.go at lines 37-38, where the cataloger iterates over files and matches a glob. Trace the existing cataloger flow and identify how a find-by-glob operation should fit there. Done means the Nix cataloger uses find by glob instead of checking every file individually.

Written by the indexing model from the issue text.