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_ldap_backend/ldap.yaml

@@ -0,0 +1,10 @@
+userdn: "ou=people,ou=users,dc=main,dc=unkin,dc=net"
+userattr: "uid"
+upndomain: "users.main.unkin.net"
+discoverdn: false
+groupdn: "ou=users,dc=main,dc=unkin,dc=net"
+groupfilter: "(&(objectClass=posixGroup)(memberUid={{.Username}}))"
+groupattr: "uid"
+username_as_alias: true
+default_lease_ttl: 24h
+max_lease_ttl: 168h