BuildSystem: Move all userpace libraries under the userspace directory

As the number of libraries is increasing, root directory starts to
expand. This adds better organization for libraries

userspace/libraries/LibC/include/bits/printf.h

@@ -0,0 +1,15 @@
+#ifndef _BITS_PRINTF_H
+#define _BITS_PRINTF_H 1
+
+#include <sys/cdefs.h>
+
+__BEGIN_DECLS
+
+#include <stdarg.h>
+#include <stddef.h>
+
+int printf_impl(const char* format, va_list arguments, int (*putc_fun)(int, void*), void* data);
+
+__END_DECLS
+
+#endif