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/pki_mount_only/pki_root.yaml

@@ -0,0 +1,17 @@
+description: "PKI Root CA"
+max_lease_ttl_seconds: 315360000  # 10 years
+issuer_ref: "default"
+issuing_certificates:
+  - "https://vault.service.consul:8200/v1/pki_root/ca"
+crl_distribution_points:
+  - "https://vault.service.consul:8200/v1/pki_root/crl"
+ocsp_servers: []
+enable_templating: false
+default_issuer_ref: null
+default_follows_latest_issuer: false
+crl_expiry: "72h"
+crl_disable: false
+ocsp_disable: false
+auto_rebuild: false
+enable_delta: false
+delta_rebuild_interval: null