[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/nextcloud/module/chart_values.yaml

@@ -0,0 +1,65 @@
+nextcloud:
+  host: nextcloud.viktorbarzin.me
+  trustedDomains:
+    - nextcloud.viktorbarzin.me
+  # mail:
+  #   enabled: true
+  #   # the user we send email as
+  #   fromAddress: nextcloud@viktorbarzin.me
+  #   # the domain we send email from
+  #   domain: viktorbarzin.me
+  #   smtp:
+  #     host: mail.viktorbarzin.me
+  #     secure: starttls
+  #     port: 587
+  #     authtype: LOGIN
+  #     name: nextcloud@viktorbarzin.me
+  #     password:
+  extraEnv:
+    - name: TRUSTED_PROXIES
+      value: "10.0.0.0/8"
+    # - name: mail_smtpdebug
+    #   value: "true"
+    # - name: loglevel
+    #   value: "0"
+
+# internalDatabase:
+#   enabled: false
+
+externalRedis:
+  enabled: true
+  host: redis.redis.svc.cluster.local
+
+# Currently not in use; we use the nextcloud.db sqlite3
+externalDatabase:
+  enabled: false
+  type: mysql
+  host: mysql.dbaas.svc.cluster.local
+  user: nextcloud
+  password: ${db_password}
+  databse: nextcloud
+
+persistence:
+  enabled: true
+  existingClaim: nextcloud-data-pvc
+
+  accessMode: ReadWriteOnce
+  size: 100Gi
+
+startupProbe:
+  enabled: true
+  initialDelaySeconds: 10
+  periodSeconds: 10
+  timeoutSeconds: 5
+  failureThreshold: 30
+  successThreshold: 1
+
+podAnnotations:
+  diun.enable: "true"
+  diun.include_tags: "^[0-9]+(?:.[0-9]+)?(?:.[0-9]+)?.*"
+
+collabora:
+  enabled: false # Using onlyoffice instead
+
+cronjob:
+  enabled: true