Update metadata.json

[Stell0]

Removed AI category since is not a NethServer 8 category

[Stell0]

Hermes is multi purpose, technically also those categories could fit:

        "system_administration": if you give it a linux mcp or ssh access does a good job
        "office": can edit office files from multiple sources
        "collaboration": can work on calendar and contacts
        "documentation": is good at reading/writing documentation
        "database": it sure can manage a database
        "storage": everithing is storage
        "monitoring": with a cron job, can do monitoring and send alerts
        "web": can do web search or create and edit websites
        "communication": has multiple messaging interfaces
        "security": can asses security if you want
        "multimedia": can read multimedia files or create them with pipelines

should I add everything?