Performance: Increase database buffer pools for Nextcloud and Zabbix

- Nextcloud MariaDB: 128MB → 4GB buffer pool
- Zabbix MariaDB: 128MB → 3GB buffer pool
- Added innodb-log-file-size=512M for better write performance
- Added max-connections=200 for better concurrency
- Created performance.cnf for Zabbix with additional optimizations

Expected improvement: 3-6x faster database queries
Impact: Better responsiveness for Nextcloud and Zabbix web UI

compose_files/nextcloud.yml

@@ -15,6 +15,7 @@ services:
           #options:
           #loki-url: "http://localhost:3100/loki/api/v1/push"
     image: mariadb:10.5
+    command: --innodb-buffer-pool-size=4G --innodb-log-file-size=512M --max-connections=200
     volumes:
       - /home/icke/mariadb-nextcloud/db:/var/lib/mysql
       - /etc/localtime:/etc/localtime:ro