Add method name & prefix to StorageFunction (#182)

* Add methods & prefix to StorageFunction

* Match method/section to exposed names

* Export method/section on extrinsic & jsonrpc

* PR comment prefix -> section

packages/api-provider/src/mock/state.ts

@@ -18,8 +18,8 @@ const SUBSCRIPTIONS: string[] = Array.prototype.concat.apply(
       .filter((method) =>
         method.isSubscription
       )
-      .map(({ name, section }) =>
-        `${section}_${name}`
+      .map(({ method, section }) =>
+        `${section}_${method}`
       )
   )
 );