turning a lot of includes into forward declares

src/common/Common.hpp

@@ -3,7 +3,6 @@
 #include "common/Aliases.hpp"
 #include "common/Outcome.hpp"
 #include "common/ProviderId.hpp"
-#include "debug/Log.hpp"
 
 #include <QString>
 #include <QWidget>
@@ -39,4 +38,7 @@ std::weak_ptr<T> weakOf(T *element)
     return element->shared_from_this();
 }
 
+struct Message;
+using MessagePtr = std::shared_ptr<const Message>;
+
 }  // namespace chatterino