fix(gatsby): Set a timeout of 15 seconds on queries (#23036)

Query resolvers can hang indefinitely right now which can be confusing to debug as there's no indication of what's happening.

With a timeout set, eventually the hanging query will fail with an error like this which should help people figure out where to investigate

packages/gatsby/src/query/queue.js

@@ -10,6 +10,7 @@ const createBaseOptions = () => {
     concurrent: Number(process.env.GATSBY_EXPERIMENTAL_QUERY_CONCURRENCY) || 4,
     // eslint-disable-next-line new-cap
     store: FastMemoryStore(),
+    maxTimeout: 15000,
   }
 }