LibIPC: Start fleshing out a separate IPC library

This will be a place to put object serialization/deserialization logic,
message parsing, endpoint management, etc.

Libraries/LibIPC/IMessage.h

@@ -0,0 +1,18 @@
+#pragma once
+
+#include <AK/AKString.h>
+#include <AK/ByteBuffer.h>
+
+class IMessage {
+public:
+    virtual ~IMessage();
+
+    const String& name() const { return m_name; }
+    virtual ByteBuffer encode() = 0;
+
+protected:
+    IMessage();
+
+private:
+    String m_name;
+};