New state plugin callback for pagination.

* You need to change all statedata plugin callback for the new pagination feature
  * If you dont use pagination you can ignore the values of the new parameters
  * See [User manual pagination](https://clixon-docs.readthedocs.io/en/latest/misc.html#pagination)
  * The updated callback signature is as follows:
  ```
  int statedata(clicon_handle     h,
                cvec             *nsc,
	        char             *xpath,
	        pagination_mode_t pagmode,   // NEW
	        uint32_t          offset,    // NEW
	        uint32_t          limit,     // NEW
	        uint32_t         *remaining, // NEW
	        cxobj            *xstate)
  ```

example/main/example_backend_nacm.c

@@ -180,6 +180,10 @@ int
 nacm_statedata(clicon_handle h, 
 	       cvec         *nsc,
 	       char         *xpath,
+	       pagination_mode_t pagmode,
+	       uint32_t        offset,
+	       uint32_t        limit,
+	       uint32_t       *remaining, 
 	       cxobj        *xstate)
 {
     int     retval = -1;