Enchance /crawl API endpoint with local server information (RIPD-1644):

The /crawl API endpoint allows developers to examine the structure of
the XRP Ledger's overlay network.

This commit adds additional information about the local server to the
/crawl endpoint, making it possible for developers to create data-rich
network-wide status dashboards.

Related:
 - https://developers.ripple.com/peer-protocol.html
 - https://github.com/ripple/rippled-network-crawler

src/ripple/app/misc/impl/ValidatorSite.cpp

@@ -320,7 +320,8 @@ ValidatorSite::parseJsonResponse (
         body["manifest"].asString (),
         body["blob"].asString (),
         body["signature"].asString(),
-        body["version"].asUInt());
+        body["version"].asUInt(),
+        sites_[siteIdx].activeResource->uri);
 
     sites_[siteIdx].lastRefreshStatus.emplace(
         Site::Status{clock_type::now(), disp, ""});