[B-78574] Move tenant entries check to servlet filter in cloudfeeds-atom...

...hopper

   - Modified Transform Utils to rely completely on firstbyte rather than status code as the filter call is async (Not completely related to story)
   - Added TenantedEntryVerificationFilter to verify tenant id from response against tenantId in request
Does this method not work? 
http://stackoverflow.com/questions/6390339/how-to-query-xml-using-namespaces-in-java-with-xpath

```
XPathFactory factory = XPathFactory.newInstance();
XPath xpath = factory.newXPath();
HashMap<String, String> prefMap = new HashMap<String, String>() {{
    put("foobar", "http://www.w3c.org/2005/Atom");
}};
SimpleNamespaceContext namespaces = new SimpleNamespaceContext(prefMap);
xpath.setNamespaceContext(namespaces);
XPathExpression expr = xpath.compile("/foobar:entry/foobar:category.....");
```
I am thinking the input XML does NOT have to have prefix "foobar" and the API will match the actual namespace. You are just referring it in the XPath with prefix "foobar". 

The above is more explicit. I.e: we are looking only for the entry element that belongs to the http://www.w3c.org/2005/Atom namespace. So we are not accidentally grabbing other elements that happened to have the same name.

If the above does not work, then my 2nd choice would be to do /local-name()='entry'/local-name()='category'/.... etc