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/kv/service/media-apps/sonarr/read.yaml

@@ -0,0 +1,10 @@
+# Allow reading Sonarr configuration
+---
+rules:
+  - path: "kv/data/service/media-apps/sonarr"
+    capabilities:
+      - read
+
+auth:
+  k8s/au/syd1:
+    - media-apps