Core/Dungeon Finder: Use lfg namespace to encapsulate all LFG classes, structs and enums

src/server/game/DungeonFinding/LFGScripts.cpp

@@ -29,6 +29,9 @@
 #include "ObjectAccessor.h"
 #include "WorldSession.h"
 
+namespace lfg
+{
+
 LFGPlayerScript::LFGPlayerScript() : PlayerScript("LFGPlayerScript")
 {
 }
@@ -208,3 +211,5 @@ void LFGGroupScript::OnInviteMember(Group* group, uint64 guid)
     if (leader && !gguid)
         sLFGMgr->LeaveLfg(leader);
 }
+
+} // namespace lfg