feature/add impl (#6)

* format code

* with object gen and args

* add implementation

* add rust generator

* reset generated code

* add basic output

* reset output

* add object

* add format function

* with opts

* fix vec

* add context to unwrap

* fix arguments

* with function body

* first complete generation: Still missing Vec<Obj>

* run full alpine

* add roadmap item

crates/dagger-codegen/src/generator.rs

@@ -0,0 +1,21 @@
+use std::sync::Arc;
+
+use dagger_core::introspection::Schema;
+
+pub trait Generator {
+    fn generate(&self, schema: Schema) -> eyre::Result<String>;
+}
+
+pub type DynGenerator = Arc<dyn Generator + Send + Sync>;
+
+pub trait FormatTypeRefs {
+    fn format_kind_list(representation: &str) -> String;
+    fn format_kind_scalar_string(representation: &str) -> String;
+    fn format_kind_scalar_int(representation: &str) -> String;
+    fn format_kind_scalar_float(representation: &str) -> String;
+    fn format_kind_scalar_boolean(representation: &str) -> String;
+    fn format_kind_scalar_default(representation: &str, ref_name: &str, input: bool) -> String;
+    fn format_kind_object(representation: &str, ref_name: &str) -> String;
+    fn format_kind_input_object(representation: &str, ref_name: &str) -> String;
+    fn format_kind_enum(representation: &str, ref_name: &str) -> String;
+}