feat: add serde derive to Score types

This commit adds `serde` dependency and derives `Serialize` trait for `Score` types. This is necessary for serialization and deserialization of these types, which is required to display Scores to various user interfaces

- Added `serde` dependency to `harmony_types/Cargo.toml`.
- Added `serde::Serialize` derive macro to `MacAddress` in `harmony_types/src/lib.rs`.
- Added `serde::Serialize` derive macro to `Config` in `opnsense-config/src/config/config.rs`.
- Added `serde::Serialize` derive macro to `Score` in `harmony_types/src/lib.rs`.
- Added `serde::Serialize` derive macro to `Config` and `Score` in relevant modules.
- Added placeholder `todo!()` implementations for `serialize` methods. These will be implemented in future commits.

opnsense-config/src/config/config.rs

@@ -11,6 +11,7 @@ use crate::{
 use log::{debug, info, trace, warn};
 use opnsense_config_xml::OPNsense;
 use russh::client;
+use serde::Serialize;
 
 use super::{ConfigManager, OPNsenseShell};
 
@@ -21,6 +22,15 @@ pub struct Config {
     shell: Arc<dyn OPNsenseShell>,
 }
 
+impl Serialize for Config {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: serde::Serializer,
+    {
+        todo!()
+    }
+}
+
 impl Config {
     pub async fn new(
         repository: Arc<dyn ConfigManager>,