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.

flake.nix

@@ -67,6 +67,7 @@
         ./parts/hosts.nix
         ./parts/packages.nix
         ./parts/devshells.nix
+        ./parts/images.nix
       ];
     };
 }