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/DHCP/dhclient.conf

@@ -0,0 +1,6 @@
+option rfc3442-classless-static-routes code 121 = array of unsigned integer 8;
+
+send host-name = gethostname();
+request subnet-mask, broadcast-address, time-offset, routers,
+        domain-name, host-name,
+        rfc3442-classless-static-routes;