cleanup: include/: move json.h to data/json.h

move json.h to data/json.h and
create a shim for backward-compatibility.

No functional changes to the headers.
A warning in the shim can be controlled with CONFIG_COMPAT_INCLUDES.

Related to #16539

Signed-off-by: Anas Nashif <anas.nashif@intel.com>
diff --git a/lib/os/json.c b/lib/os/json.c
index d5df75f..8860b60 100644
--- a/lib/os/json.c
+++ b/lib/os/json.c
@@ -15,7 +15,7 @@
 #include <string.h>
 #include <zephyr/types.h>
 
-#include "json.h"
+#include <data/json.h>
 
 struct token {
 	enum json_tokens type;