feat(subscriptions): add cmd to gen json schema

This commit introduces the 'notification-schema' command to generate a
JSON schema of the Notification struct which gets sent when notifying
subscribers of updates.

komorebi-core/Cargo.toml

@@ -12,6 +12,7 @@ serde = { version = "1", features = ["derive"] }
 serde_json = "1"
 serde_yaml = "0.8"
 strum = { version = "0.23", features = ["derive"] }
+schemars = "0.8"
 
 [dependencies.windows]
 version = "0.30"