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.lock

@@ -1158,6 +1158,7 @@ dependencies = [
  "rust-ipmi",
  "semver",
  "serde",
+ "serde-value",
  "serde_json",
  "serde_yaml",
  "tokio",
@@ -1195,6 +1196,9 @@ dependencies = [
 [[package]]
 name = "harmony_types"
 version = "0.1.0"
+dependencies = [
+ "serde",
+]
 
 [[package]]
 name = "hashbrown"