AK: Rename the common integer typedefs to make it obvious what they are.

These types can be picked up by including <AK/Types.h>:

* u8, u16, u32, u64 (unsigned)
* i8, i16, i32, i64 (signed)

Kernel/Net/LoopbackAdapter.cpp

@@ -18,7 +18,7 @@ LoopbackAdapter::~LoopbackAdapter()
 {
 }
 
-void LoopbackAdapter::send_raw(const byte* data, int size)
+void LoopbackAdapter::send_raw(const u8* data, int size)
 {
     dbgprintf("LoopbackAdapter: Sending %d byte(s) to myself.\n", size);
     did_receive(data, size);