Migrate from Boards to Variant, remove hardcoded versions, remove customn directories and some cleanup

mcu-gate.yaml

@@ -11,14 +11,9 @@ esphome:
   comment: ${comment}
 
 esp32:
-  board: m5stack-atom
+  variant: esp32
   framework:
     type: esp-idf
-    version: 5.3.2
-    platform_version: 53.03.11
-
-external_components:
-  - source: components
   
 packages:
   common: !include common/common.yaml