feat!(core): Use new AST structure

Derive Expr methods using a derive proc-macro. These macros are present in
the `argus-derive` crate, but the traits are defined in `argus-core`

argus-core/Cargo.toml

@@ -10,6 +10,8 @@ paste = "1.0.12"
 num-traits = "0.2.15"
 thiserror = "1.0.39"
 proptest = { version = "1.1.0", optional = true }
+enum_dispatch = "0.3.11"
+argus-derive = { version = "0.1.0", path = "../argus-derive" }
 
 [dev-dependencies]
 argus-core = { path = ".", features = ["arbitrary"] }