New dimmer with backlight and 1000 max brightness (#5693)

Hello, working on this new device to cover a new dimmer switch I bought.
The current "Simple Dimmer" goes from 10 to 255 brightness, while this
one has a maximum of 1000, so the current max on home assistant is
actually only about 25% brightness of my device. I'm also adding the
backlight configuration for the dimmer which is not available on "Simple
Dimmer"

I'm still trying to test it, for some reason I wasn't able to make it
show up for me as an option on HA, even though I see the file on the
tuya-local folder. Opening the PR as draft for now while I try to fix
it.

---------

Co-authored-by: Jason Rumney <make-all@users.noreply.github.com>

custom_components/tuya_local/devices/liwokit_dimmerswitch.yaml

@@ -0,0 +1,31 @@
+name: Backlit dimmer
+products:
+  - id: g5tdfvf5g4osvagd
+    manufacturer: Liwokit
+    model: "Backlit Dimmer Switch"
+entities:
+  - entity: light
+    dps:
+      - id: 1
+        name: switch
+        type: boolean
+      - id: 2
+        name: brightness
+        type: integer
+        range:
+          min: 10
+          max: 1000
+  - entity: select
+    category: config
+    translation_key: light_mode
+    dps:
+      - id: 21
+        name: option
+        type: string
+        mapping:
+          - dps_val: relay
+            value: state
+          - dps_val: pos
+            value: locator
+          - dps_val: none
+            value: "off"