Add Linode host configuration and WireGuard setup

- Introduced new configuration files for Linode host, including hardware configuration, toggles, and WireGuard settings.
- Updated flake.nix to include the new images.nix file for Linode image generation.
- Adjusted SSH key paths and secrets management for WireGuard to ensure proper integration with the new host setup.
- Enhanced firewall rules and NAT configuration for WireGuard to improve security and connectivity.

modules/modules.nix

@@ -63,6 +63,7 @@ in
         server = "enp0s31f6";
         miniserver = "enp2s0";
         workstation = "enp5s0";
+        linode = "eth0";
       };
       description = "Set of network interface names for all my computers.";
     };