feat(wasm-backend, app-service)!: use String for wasi env vars + require Clone for Function trait (#333)

* use String instead of Vec<u8> for wasi envs

* require Clone for Function trait

* fmt

* pr fixes

crates/wasm-backend-traits/src/exports.rs

@@ -21,6 +21,7 @@ use crate::DelayedContextLifetime;
 use crate::WasmBackend;
 
 /// Contains Wasm exports necessary for internal usage.
+#[derive(Clone)]
 pub enum Export<WB: WasmBackend> {
     Memory(<WB as WasmBackend>::Memory),
     Function(<WB as WasmBackend>::Function),

crates/wasm-backend-traits/src/function.rs

@@ -23,7 +23,7 @@ use crate::WValue;
 
 /// A Wasm function handle, it can be either a function from a host or an export from an `Instance`.
 /// As it is only a handle to an object in `Store`, cloning is cheap
-pub trait Function<WB: WasmBackend>: Send + Sync {
+pub trait Function<WB: WasmBackend>: Send + Sync + Clone {
     /// Creates a new function with dynamic signature.
     /// The signature check is performed at runtime.
     fn new<F>(store: &mut impl AsContextMut<WB>, sig: FuncSig, func: F) -> Self

crates/wasm-backend-traits/src/wasi.rs

@@ -41,8 +41,8 @@ pub trait WasiImplementation<WB: WasmBackend> {
 
 #[derive(Default)]
 pub struct WasiParameters {
-    pub args: Vec<Vec<u8>>,
-    pub envs: HashMap<Vec<u8>, Vec<u8>>,
+    pub args: Vec<String>,
+    pub envs: HashMap<String, String>,
     pub preopened_files: HashSet<PathBuf>,
     pub mapped_dirs: HashMap<String, PathBuf>,
 }