Feature update backend (#3)

* Update Terraform backend configuration and add backend.conf sample

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Co-authored-by: Damien A <sepales.pret0h@icloud.com>

terraform/provider.tf

@@ -0,0 +1,9 @@
+provider "aws" {
+  region     = var.AWS_REGION
+  access_key = var.AWS_ACCESS_KEY
+  secret_key = var.AWS_SECRET_KEY
+}
+
+terraform {
+  backend "s3" {}
+}