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

config/auth_approle_role/approle/incus_cluster.yaml

@@ -0,0 +1,12 @@
+token_policies:
+  - "default_access"
+  - "kv/service/incus/incus-cluster-join-tokens"
+token_ttl: 60
+token_max_ttl: 120
+bind_secret_id: false
+token_bound_cidrs:
+  - "10.10.12.200/32"
+  - "198.18.13.77/32"
+  - "198.18.13.78/32"
+  - "198.18.13.79/32"
+use_deterministic_role_id: false