Add Valkey infrastructure role as Redis-compatible cache service

- Implemented complete Valkey infrastructure role following PostgreSQL patterns
- Provides 100% Redis-compatible high-performance data structure store
- Configured for multi-application support with database isolation
- Security-focused: localhost-only binding, password auth, systemd hardening
- Arch Linux compatible: uses native Valkey package with Redis compatibility
- Database allocation strategy: DB 0 reserved, DB 1+ for applications
- Full systemd integration with security overrides and proper service management
- Redis client compatibility maintained for seamless application integration
- Ready for Authentik and future container workloads requiring cache services

site.yml

@@ -8,14 +8,16 @@
   gather_facts: yes
   
   roles:
-    # # Infrastructure services
+    # Infrastructure services
     # - role: postgresql
     #   tags: ['postgresql', 'infrastructure', 'database']
-    # # - role: caddy
-    # #   tags: ['caddy', 'infrastructure', 'web']
-    # 
+    - role: valkey
+      tags: ['valkey', 'redis', 'infrastructure', 'cache']
+    # - role: caddy
+    #   tags: ['caddy', 'infrastructure', 'web']
+    
     # Application services  
-    - role: gitea
-      tags: ['gitea', 'git', 'development']
+    # - role: gitea
+    #   tags: ['gitea', 'git', 'development']
     # - role: sigvild-gallery
     #   tags: ['sigvild', 'gallery', 'wedding']