Linking into nimbledeps/pkgs does not work
In local mode (ie: using `nimble install -l`), I should be able to symlink a package (ie: a directory with `pkg.nimble` in it) into the `./nimbledeps/pkgs` directory and have `nimble install` use that package instead of searching `package.json` files for it.

Currently, I get:
```
Prompt: my-package not found in any local packages.json, check internet for updated packages? [y/N]
```