Normalize printed rootLocation

Reusing libkiwix's normalizeRootUrl() to display a more reliable representation of the
rootLocation the InternalServer will be using.

Can't reuse server.m_root as it is private.

src/server/kiwix-serve.cpp

@@ -103,6 +103,16 @@ std::string loadCustomTemplate (std::string customIndexPath) {
   return indexTemplateString;
 }
 
+inline std::string normalizeRootUrl(std::string rootUrl)
+{
+  while ( !rootUrl.empty() && rootUrl.back() == '/' )
+    rootUrl.pop_back();
+
+  while ( !rootUrl.empty() && rootUrl.front() == '/' )
+    rootUrl = rootUrl.substr(1);
+  return rootUrl.empty() ? rootUrl : "/" + rootUrl;
+}
+
 volatile sig_atomic_t waiting = false;
 volatile sig_atomic_t libraryMustBeReloaded = false;
 
@@ -393,7 +403,7 @@ int main(int argc, char** argv)
     exit(1);
   }
 
-  std::string url = "http://" + server.getAddress() + ":" + std::to_string(server.getPort()) + rootLocation;
+  std::string url = "http://" + server.getAddress() + ":" + std::to_string(server.getPort()) + normalizeRootUrl(rootLocation);
   std::cout << "The Kiwix server is running and can be accessed in the local network at: "
             << url << std::endl;