feat(welltobe_cat_feeder): add meal plan entity

Add the meal plan entity on dp 1.
As this is not normally sent by the device and is in an undocumented
binary format, make it disabled by default, but it is there if the users
choose to enable it.

Issue #3702

custom_components/tuya_local/devices/welltobe_cat_feeder.yaml

@@ -16,6 +16,15 @@ entities:
         range:
           min: 1
           max: 6
+  - entity: text
+    name: Meal plan
+    hidden: true
+    category: config
+    dps:
+      - id: 1
+        type: base64
+        optional: true
+        name: value
   - entity: switch
     name: Slow feed
     icon: "mdi:speedometer-slow"