[discussion!] autoload support

[mrcjkb]

          Discussion for another issue:

Perhaps we don't actually need this.
It could potentially lead to the subtle issues, because the packadd is delayed (it's async). Neovim only searches for colorschemes in pack/*/opt, but not autoload scripts or tree-sitter parsers, which is why I had added this.

But perhaps it's better for now not to support autoload scripts as dependencies. It's not really common in the lua ecosystem anyway.

Originally posted by @mrcjkb in #562 (comment)