Move shield library into new repository

[claysmalley]

The shield generator has taken on a life of its own. Now that it's a separate codepath and published as an NPM package, it should be given its own repository. This will make it simpler to track issues and reuse the code in other projects.

• [ ] Determine more compact format for shields.json
• [ ] Check in shields.json, remove shield_defs.js
• [ ] Transfer code, issues and history to new repository
• [ ] Reconfigure Github, NPM
• [ ] Transition repository to new organization
• [ ] Remove shieldlib/

[ZeLonewolf]

Thanks for writing this up. I support this initiative. I think we should also extend the work in the pending #881 to also report on the size of the shields.json file so we have a metric for compactness. After all, the download time of that file is part of the overall map load time.

[adamfranco]

Another benefit of this move is easier filtering/monitoring of issues -- shields significantly dominate the issue queue and not all interested in Americana are as engaged on the topic. 😉

[ZeLonewolf]

To be fair, most of the shield traffic is on the design side which would still be in this repo.