Migrate from Redis to Couchbase for data storage

Replaces Redis with Couchbase as the primary data store. Updates environment variables, dependencies, and Docker Compose configuration to use Couchbase. Refactors repository and model classes to use Couchbase APIs, removes Redis utility and related code, and adds Couchbase utility for collection management. Updates AdminRepository to use 'admin' as the key instead of an empty string.

compose.dev.yml

@@ -1,12 +1,18 @@
 services:
-  redis:
-    image: redis:7.2-alpine
+  couchbase:
+    image: couchbase:community-7.6.2
+    env_file:
+      - .env
     ports:
-      - "6379:6379"
+      - "8091-8097:8091-8097"
+      - "9123:9123"
+      - "11207:11207"
+      - "11210:11210"
+      - "11280:11280"
+      - "18091-18097:18091-18097"
     volumes:
-      - redis_data:/data
+      - couchbase_data:/opt/couchbase/var
     restart: unless-stopped
-    command: redis-server --appendonly yes
 
 volumes:
-  redis_data:
+  couchbase_data: