fix(core): Fix async panic on blocking #19

Replaced internal threads with tokio spawn functions

crates/dagger-sdk/tests/mod.rs

@@ -2,7 +2,7 @@ use dagger_sdk::{connect, ContainerExecOptsBuilder};
 
 #[tokio::test]
 async fn test_example_container() {
-    let client = connect().unwrap();
+    let client = connect().await.unwrap();
 
     let alpine = client.container().from("alpine:3.16.2");