Fix: Generate users_database.yml in secrets folder with proper variables

- Move users_database.yml template from config/ to secrets/ folder
- Authelia configuration expects users file at /secrets/users_database.yml
- Replace hardcoded values in configuration.yml with variables:
  - jwt_secret, session secret, storage encryption_key
  - Domain references (kelinreij.duckdns.org → ${DOMAIN})
- Update deploy script to not move config files (already in subdirectories)
- Fix sed command path to target config/configuration.yml
- Remove unnecessary mkdir and mv commands from deploy_core()

This ensures Authelia uses the correctly generated file with user credentials.

docker-compose/core/authelia/secrets/users_database.yml

@@ -1,19 +1,12 @@
-# yamllint disable rule:line-length
----
 ###############################################################
 #                         Users Database                      #
 ###############################################################
 
-# This file can be used if you do not have an LDAP set up.
-
 users:
-  authelia:
-    disabled: false
-    displayname: "Test User"
-    password: "$argon2id$v=19$m=32768,t=1,p=8$eUhVT1dQa082YVk2VUhDMQ$E8QI4jHbUBt3EdsU1NFDu4Bq5jObKNx7nBKSn1EYQxk"  # Password is 'authelia'
-    email: authelia@authelia.com
+  ${AUTHELIA_ADMIN_USER}:
+    displayname: "${AUTHELIA_ADMIN_USER}"
+    password: "${AUTHELIA_ADMIN_PASSWORD_HASH}"
+    email: ${AUTHELIA_ADMIN_EMAIL}
     groups:
       - admins
-      - dev
-...
-# yamllint enable rule:line-length
+      - users