feat: add graphql support

crates/mcpaas-adapter-graphql/src/lib.rs

@@ -1,3 +1,7 @@
-pub fn crate_name() -> &'static str {
-    "mcpaas-adapter-graphql"
-}
+mod client;
+mod error;
+mod model;
+
+pub use client::GraphqlAdapter;
+pub use error::GraphqlAdapterError;
+pub use model::{GraphqlRequest, GraphqlResponse};