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.

Cargo.toml

@@ -30,6 +30,7 @@ url = "2.5.4"
 kube = "0.98.0"
 k8s-openapi = { version = "0.24.0", features = [ "v1_30" ] }
 serde_yaml = "0.9.34"
+serde-value = "0.7.0"
 http = "1.2.0"
 
 [workspace.dependencies.uuid]