Add support for multiple URLs in an entry

* Fixes #398

The new Browser Integration entry settings page has a list view with any additional URL's. These URL's are added to the entry attributes with KP2A_URL_<counter>, which means those are directly compatible with Keepass2Android.

tests/TestBrowser.h

@@ -42,6 +42,7 @@ private slots:
     void testSortPriority();
     void testSearchEntries();
     void testSearchEntriesWithPort();
+    void testSearchEntriesWithAdditionalURLs();
     void testSortEntries();
     void testGetDatabaseGroups();