Remove QueryString

QueryString is an error-prone library that was
leftover from crow. Replace it with boost::url,
a header only library based and written by the
one of the authors of boost beast.

Tested: Verified logging paging still worked
as expected

Change-Id: I47c225089aa7d0f7d2299142f91806294f879381
Signed-off-by: James Feist <james.feist@linux.intel.com>
diff --git a/redfish-core/lib/event_service.hpp b/redfish-core/lib/event_service.hpp
index d3ed416..4d9d4d9 100644
--- a/redfish-core/lib/event_service.hpp
+++ b/redfish-core/lib/event_service.hpp
@@ -471,13 +471,16 @@
         subValue->protocol = "Redfish";
         subValue->retryPolicy = "TerminateAfterRetries";
 
-        char* filters = req.urlParams.get("$filter");
-        if (filters == nullptr)
+        boost::urls::url_view::params_type::iterator it =
+            req.urlParams.find("$filter");
+        if (it == req.urlParams.end())
         {
             subValue->eventFormatType = "Event";
         }
+
         else
         {
+            std::string filters = it->value();
             // Reading from query params.
             bool status = readSSEQueryParams(
                 filters, subValue->eventFormatType, subValue->registryMsgIds,