Remove backend.tf from child module

- backend.tf should only exist in root modules, not child modules
- Removes warning: Backend configuration ignored
- This module is only used as a child module via git source

terraform/backend.tf

@@ -1,21 +0,0 @@
-terraform {
-  backend "s3" {
-    endpoints = {
-      s3 = "https://minio.bsdserver.nl:443"
-    }
-
-    bucket = "home-terraform"
-    key    = "home/security/encryption/certificate-automation.tfstate"
-
-    # Configure credentials via environment variables:
-    # export AWS_ACCESS_KEY_ID="your-access-key"
-    # export AWS_SECRET_ACCESS_KEY="your-secret-key"
-
-    region                      = "main"
-    skip_credentials_validation = true
-    skip_metadata_api_check     = true
-    skip_requesting_account_id  = true
-    skip_region_validation      = true
-    use_path_style              = true
-  }
-}