add a link to recrawl index entry to metadata html page

- to allow manually renew index content for this url (e.g. in case it is a remote search result with metadata only)
- use simply a  QuickCrawlLink_p javascript snippet (minimalistic 1st solution)

source/net/yacy/cora/federate/solr/responsewriter/HTMLResponseWriter.java

@@ -156,6 +156,12 @@ public class HTMLResponseWriter implements QueryResponseWriter {
     private static final void writeDoc(Writer writer, LinkedHashMap<String, String> tdoc, String title) throws IOException {
         writer.write("<form name=\"yacydoc" + title + "\" method=\"post\" action=\"#\" enctype=\"multipart/form-data\" accept-charset=\"UTF-8\">\n");
         writer.write("<fieldset>\n");
+        
+        // add a link to re-crawl this url (in case it is a remote metadata only entry)
+        String sku = tdoc.get(CollectionSchema.sku.getSolrFieldName());
+        final String jsc= "javascript:w = window.open('/QuickCrawlLink_p.html?indexText=on&indexMedia=on&crawlingQ=on&followFrames=on&obeyHtmlRobotsNoindex=on&xdstopw=on&title='+escape('"+title+"')+'&url='+escape('"+sku+"'),'_blank','height=250,width=600,resizable=yes,scrollbar=no,directory=no,menubar=no,location=no');w.focus();";
+        writer.write("<div class='btn btn-default btn-sm' style='float:right' onclick=\""+jsc+"\">re-crawl url</div>\n");
+
         writer.write("<h1 property=\"dc:Title\">" + title + "</h1>\n");
         writer.write("<dl>\n");
         for (Map.Entry<String, String> entry: tdoc.entrySet()) {