fix(k8s_anywhere): Ensure k3d cluster is started before use

- Refactor k3d cluster management to explicitly start the cluster.
- Introduce `start_cluster` function to ensure cluster is running before operations.
- Improve error handling and logging during cluster startup.
- Update `create_cluster` and other related functions to utilize the new startup mechanism.
- Enhance reliability and prevent potential issues caused by an uninitialized cluster.
- Add `run_k3d_command` to handle k3d commands with logging and error handling.

opnsense-config/src/config/config.rs

@@ -23,7 +23,7 @@ pub struct Config {
 }
 
 impl Serialize for Config {
-    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    fn serialize<S>(&self, _serializer: S) -> Result<S::Ok, S::Error>
     where
         S: serde::Serializer,
     {