Add Licensed To Help Verify Prod Licenses (#128)

* Add Licensed Workflow and config

* manual validation of dependencies

* Ignore Generated Files in Git PR's

* update contributing.md

.licensed.yml

@@ -0,0 +1,14 @@
+sources:
+  npm: true
+
+allowed:
+  - apache-2.0
+  - bsd-2-clause
+  - bsd-3-clause
+  - isc
+  - mit
+  - cc0-1.0
+  - unlicense
+
+reviewed:
+  npm: