docs: add Conway queries to README (#771)

Author: agaffney

README.md

@@ -72,6 +72,13 @@ This is not an exhaustive list of existing and planned features, but it covers t
         - [ ] Pool state
         - [ ] Stake snapshots
         - [ ] Pool distribution
+        - [ ] Constitution
+        - [ ] Governance state
+        - [ ] DRep state
+        - [ ] DRep stake distribution
+        - [ ] SPO stake distribution
+        - [ ] Committee state
+        - [ ] Treasury
 - [ ] Ledger
   - [ ] Eras
     - [X] Byron