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.

AK/kmalloc.h

@@ -1,25 +1,26 @@
 #pragma once
 
 #ifdef KERNEL
-#define AK_MAKE_ETERNAL \
-public: \
-    void* operator new(size_t size) { return kmalloc_eternal(size); } \
-private:
+#    define AK_MAKE_ETERNAL                                               \
+    public:                                                               \
+        void* operator new(size_t size) { return kmalloc_eternal(size); } \
+                                                                          \
+    private:
 #else
-#define AK_MAKE_ETERNAL
+#    define AK_MAKE_ETERNAL
 #endif
 
 #ifdef KERNEL
-#include <Kernel/kmalloc.h>
+#    include <Kernel/kmalloc.h>
 #else
-#include <stdlib.h>
+#    include <stdlib.h>
 
-#define kcalloc calloc
-#define kmalloc malloc
-#define kfree free
-#define krealloc realloc
+#    define kcalloc calloc
+#    define kmalloc malloc
+#    define kfree free
+#    define krealloc realloc
 
-#ifdef __serenity__
+#    ifdef __serenity__
 inline void* operator new(size_t size)
 {
     return kmalloc(size);
@@ -44,6 +45,6 @@ inline void* operator new(size_t, void* ptr)
 {
     return ptr;
 }
-#endif
+#    endif
 
 #endif