Vevor L2 EV charger: naming changes, merge power into one

- as per review comment, the two power sensors are the same due to being a single phase device (even if connected between 2 phases of a US power supply).  Merge them into a single sensor, with the separate reading as a "total_power" attribute.
- Remove product name from top level name, remove generic product category from product specific name.

PR #2172

custom_components/tuya_local/devices/vevor_l2_ev_charger.yaml

@@ -1,7 +1,7 @@
-name: L2 EV charger
+name: EV charger
 products:
   - id: onb9rrxfl9ywgzrg
-    name: VEVOR L2 48A EV Charger
+    name: VEVOR L2 48A
 primary_entity:
   entity: sensor
   name: Status
@@ -59,7 +59,6 @@ secondary_entities:
           min: 8
           max: 48
   - entity: sensor
-    name: Single phase power
     class: power
     category: diagnostic
     dps:
@@ -71,6 +70,11 @@ secondary_entities:
         mapping:
           - scale: 1000
             mask: "0000000000FFFFFF"
+      - id: 9
+        type: integer
+        name: total_power
+        mapping:
+          - scale: 1000
   - entity: sensor
     class: voltage
     category: diagnostic
@@ -95,17 +99,6 @@ secondary_entities:
         mapping:
           - scale: 1000
             mask: "0000FFFFFF000000"
-  - entity: sensor
-    class: power
-    category: diagnostic
-    dps:
-      - id: 9
-        type: integer
-        name: sensor
-        unit: kW
-        class: measurement
-        mapping:
-          - scale: 1000
   - entity: binary_sensor
     class: problem
     category: diagnostic