vault: deployment manifest, some docs, backup script - expected to run

on docker host

docker-30/vault/terraform/versions.tf

@@ -0,0 +1,12 @@
+terraform {
+  required_providers {
+    vault = {
+      source  = "hashicorp/vault"
+      version = "~> 4.0"
+    }
+  }
+}
+
+provider "vault" {
+  # Uses VAULT_ADDR and VAULT_TOKEN from env
+}