Add clang-format file

Also run it across the whole tree to get everything using the One True Style.
We don't yet run this in an automated fashion as it's a little slow, but
there is a snippet to do so in makeall.sh.

Applications/IRCClient/IRCWindowListModel.h

@@ -1,14 +1,15 @@
 #pragma once
 
-#include <LibGUI/GModel.h>
 #include <AK/Function.h>
+#include <LibGUI/GModel.h>
 
 class IRCClient;
 class IRCWindow;
 
 class IRCWindowListModel final : public GModel {
 public:
-    enum Column {
+    enum Column
+    {
         Name,
     };