[DB]: Add hosts

Summary

A cluster of DBs using MariaDB / Galera.

Profiles

A list of which profiles should contain:

• Core: rnl
• Filesystem: zfs-mirror
• OS: nixos
• Type: physical

Services

A list of which services will be running and any extra info (e.g. firewall ports, ...):

• MariaDB

Metadata

• Hostname: db1/db2
• System: x86_64-linux