[Keyboard] Jian keyboard (#8914)

Co-authored-by: Joel Challis <git@zvecr.com>
Co-authored-by: Drashna Jaelre <drashna@live.com>
Co-authored-by: Ryan <fauxpark@gmail.com>
Co-authored-by: Nick Brassel <nick@tzarc.org>

keyboards/jian/jian.h

@@ -0,0 +1,19 @@
+#pragma once
+
+#include "quantum.h"
+
+#ifdef KEYBOARD_jian_handwired
+  #include "handwired.h"
+#endif
+
+#ifdef KEYBOARD_jian_rev1
+  #include "rev1.h"
+#endif
+
+#ifdef KEYBOARD_jian_rev2
+#include "rev2.h"
+#endif
+
+#ifdef KEYBOARD_jian_nsrev2
+  #include "nsrev2.h"
+#endif