Move and rename xrdp_load_keyboard_layout()

xrdp_load_keyboard_layout() is used exclusively by the xup module to
work out the parameters to pass to xorgxrdp for XKB. This function
does not need to be called locally from the SEC module.

This commit moves the function to xrdp/lang.c and renames it as
xrdp_init_xkb_layout(). The module interface is modified so that xup can
call this function. Other modules do not need to call it.

vnc/vnc.h

@@ -69,6 +69,7 @@ enum vnc_resize_support_status
 };
 
 struct source_info;
+struct xrdp_client_info;
 
 /* Defined in vnc_clip.c */
 struct vnc_clipboard_data;
@@ -151,7 +152,9 @@ struct vnc
                                   int total_data_len, int flags);
     int (*server_bell_trigger)(struct vnc *v);
     int (*server_chansrv_in_use)(struct vnc *v);
-    tintptr server_dumby[100 - 28]; /* align, 100 minus the number of server
+    void (*server_init_xkb_layout)(struct vnc *v,
+                                   struct xrdp_client_info *client_info);
+    tintptr server_dumby[100 - 29]; /* align, 100 minus the number of server
                                      functions above */
     /* common */
     tintptr handle; /* pointer to self as long */