[velux] tweak read me (#14196)

Signed-off-by: Andrew Fiddian-Green <software@whitebear.ch>

bundles/org.openhab.binding.velux/doc/sitemaps.md

@@ -0,0 +1,37 @@
+
+```perl
+sitemap velux label="Velux Environment"
+{
+    Frame label="Velux Shutter and Window" {
+
+        Switch  item=V_DG_M_W_OPEN
+        Switch  item=V_DG_M_W_UNLOCKED
+        Switch  item=V_DG_M_W_CLOSED
+        Slider  item=V_DG_M_W
+    }
+    
+    Frame label="Velux Bridge Status" {
+        Text    item=V_BRIDGE_STATUS
+        Text    item=V_BRIDGE_TIMESTAMP
+        Switch  item=V_BRIDGE_RELOAD
+    }
+
+    Frame label="Velux Bridge Status" {
+        Switch  item=V_BRIDGE_DETECTION  
+        Text    item=V_BRIDGE_CHECK
+        Text    item=V_BRIDGE_SCENES
+        Text    item=V_BRIDGE_PRODUCTS
+    }
+
+    Frame label="Velux Bridge Configuration" {
+        Text    item=V_BRIDGE_FIRMWARE
+        Text    item=V_BRIDGE_IPADDRESS
+        Text    item=V_BRIDGE_SUBNETMASK
+        Text    item=V_BRIDGE_DEFAULTGW
+        Switch  item=V_BRIDGE_DHCP
+        Text    item=V_BRIDGE_WLANSSID
+        Text    item=V_BRIDGE_WLANPASSWD    
+    }
+    
+}
+```