Add support for data.link with listitems.json

[bmuenzenmeyer]

I am using Pattern Lab Node v2.0.0 on Windows, using the gulp edition.

Expected Behavior

link.patternPartial references should resolve to the expanded link when included in listitems.json, similar to data.json support added ddfd363

Actual Behavior

Links do not resolve

Steps to Reproduce

• Add a link.patternPartial key/value to listitems.json