[ci skip] Move Terraform modules into stack directories

Move all 88 service modules (66 individual + 22 platform) from
modules/kubernetes/<service>/ into their corresponding stack directories:

- Service stacks: stacks/<service>/module/
- Platform stack: stacks/platform/modules/<service>/

This collocates module source code with its Terragrunt definition.
Only shared utility modules remain in modules/kubernetes/:
ingress_factory, setup_tls_secret, dockerhub_secret, oauth-proxy.

All cross-references to shared modules updated to use correct
relative paths. Verified with terragrunt run --all -- plan:
0 adds, 0 destroys across all 68 stacks.

stacks/platform/modules/authentik/pgbouncer.ini

@@ -0,0 +1,14 @@
+[databases]
+authentik = host=postgresql.dbaas port=5432 dbname=authentik user=authentik password=${password}
+
+[pgbouncer]
+listen_addr = 0.0.0.0
+listen_port = 6432
+auth_type = md5
+auth_file = /etc/pgbouncer/userlist.txt
+pool_mode = transaction
+max_client_conn = 200
+default_pool_size = 20
+reserve_pool_size = 5
+reserve_pool_timeout = 5
+ignore_startup_parameters = extra_float_digits