Add environment configuration template and update .gitignore for new env files

serverless.yml

@@ -1,9 +1,20 @@
 service: minglarDev
- 
+
+useDotenv: true
+
+params:
+  dev:
+    stage: dev
+  test:
+    stage: test
+  uat:
+    stage: uat
+
 provider:
   name: aws
   runtime: nodejs22.x
   region: ap-south-1
+  stage: ${opt:stage, 'dev'}
   versionFunctions: false
   memorySize: 512
   # Apply Prisma layer to all functions