Use monolithic cache for Gradle User Home

- Do not restore cache when GUH exists
- Include RUNNER_OS in the cache key
- Do not save cache on exact hit
- Only save cache in the final post action
- Log before saving cache

action.yml

@@ -24,6 +24,10 @@ inputs:
     description: Whether caching downloaded Gradle distributions is enabled or not, default to 'true'
     required: false
     default: true
+  gradle-user-home-cache-enabled:
+    description: Whether caching of state in Gradle User Home is enabled, default to 'true'
+    required: false
+    default: true
   wrapper-cache-enabled:
     description: Whether caching wrapper installation is enabled or not, default to 'true'
     required: false