Use embedding api in python extension (#569)

Now embedding API is used in the Python extension, this allows us to remove ModuleData::invoke() from wasmtime-interface-types

crates/misc/py/src/module.rs

@@ -2,10 +2,10 @@
 
 extern crate alloc;
 
-use alloc::rc::Rc;
 use pyo3::prelude::*;
+use wasmtime_api as api;
 
 #[pyclass]
 pub struct Module {
-    pub module: Rc<wasmtime_environ::Module>,
+    pub module: api::HostRef<api::Module>,
 }