refactor: Remove librenms, add ansible/salt clients

- Remove all librenms references from initializers and configuration
- Keep tailscale as requested (remove netbird plans)
- Add ansible-core (already present) and salt-minion packages
- Create salt-client initializer for minion configuration
- Update roles to replace librenms-agent with salt-client
- Simplify oam initializer to only handle up2date script
- Update README to reflect new architecture and tools

Prepares infrastructure for migration to Salt configuration management
while maintaining tailscale for VPN connectivity.

💘 Generated with Crush

Assisted-by: GLM-4.6 via Crush <crush@charm.land>

initializers/system-config/NTP/ntp.conf

@@ -0,0 +1,7 @@
+driftfile /var/lib/ntp/ntp.drift
+leapfile /usr/share/zoneinfo/leap-seconds.list
+server pfv-netboot.knel.net
+restrict 127.0.0.1
+restrict ::1
+interface ignore wildcard
+interface listen 127.0.0.1