Base: Split out cpp-library template files into actual files

These were part of the postcreate script previously, but with the new
powers of sed, we can text-replace the library name and make changing
them much more convenient.

Base/res/devel/templates/cpp-library/Class1.cpp

@@ -0,0 +1,11 @@
+#include "Class1.h"
+#include <AK/Format.h>
+
+namespace $LibName {
+
+void Class1::hello()
+{
+    out("Hello friends! :^)\n");
+}
+
+}