feat: major restructuring in migration to terragrunt

- migrate from individual terraform files to config-driven terragrunt module structure
- add vault_cluster module with config discovery system
- replace individual .tf files with centralized config.hcl
- restructure auth and secret backends as configurable modules
- move auth roles and secret backends to yaml-based configuration
- convert policies from .hcl to .yaml format, add rules/auth definition
- add pre-commit hooks for yaml formatting and file cleanup
- add terragrunt cache to gitignore
- update makefile with terragrunt commands and format target

policies/transit/keys/admin.hcl

@@ -1,8 +0,0 @@
-# Allow management of keys (create, update, delete, list, and read)
-path "transit/keys/*" {
-  capabilities = ["create", "update", "delete", "read", "list"]
-}
-# Allow listing of available keys
-path "transit/keys" {
-  capabilities = ["read", "list"]
-}

policies/transit/keys/admin.yaml

@@ -0,0 +1,18 @@
+# Allow management of keys (create, update, delete, list, and read)
+---
+rules:
+  - path: "transit/keys/*"
+    capabilities:
+      - create
+      - update
+      - delete
+      - read
+      - list
+  - path: "transit/keys"
+    capabilities:
+      - read
+      - list
+
+auth:
+  approle:
+    - tf_vault