Switch to human friendly identifiers for groups

Add myself to contacts.

Author: BigBlueHat

w3c.json

@@ -1,5 +1,5 @@
  {
-    "group":      [49174]
-,   "contacts":   ["p20n"]
+    "group":      ["wg/json-ld", "cg/json-ld"]
+,   "contacts":   ["p20n", "bigbluehat"]
 ,   "repo-type":  "cg-report"
 }