feat!(cli-nats): use import and export flags

Signed-off-by: Roman Volosatovs <rvolosatovs@riseup.net>

Author: rvolosatovs

README.md

@@ -186,7 +186,7 @@ We will use the following two Rust wRPC applications using [NATS.io] transport:
 2. Serve Wasm `hello` server via [NATS.io]
 
     ```sh
-    wrpc-wasmtime nats serve rust rust ./target/wasm32-wasip1/release/hello_component_server.wasm
+    wrpc-wasmtime nats serve --export rust ./target/wasm32-wasip1/release/hello_component_server.wasm
     ```
 
     - Sample output:
@@ -197,7 +197,7 @@ We will use the following two Rust wRPC applications using [NATS.io] transport:
 3. Call Wasm `hello` server using a Wasm `hello` client via [NATS.io]:
 
     ```sh
-    wrpc-wasmtime nats run rust ./target/wasm32-wasip1/release/hello-component-client.wasm
+    wrpc-wasmtime nats run --import rust ./target/wasm32-wasip1/release/hello-component-client.wasm
     ```
 
     - Sample output in the client:
@@ -231,7 +231,7 @@ We will use the following two Rust wRPC applications using [NATS.io] transport:
 7. Call native wRPC `hello` server using Wasm `hello` client via [NATS.io]:
 
     ```sh
-    wrpc-wasmtime nats run native ./target/wasm32-wasip1/release/hello-component-client.wasm
+    wrpc-wasmtime nats run --import native ./target/wasm32-wasip1/release/hello-component-client.wasm
     ```
 
 ## Repository structure

crates/wasmtime-cli/src/nats.rs

@@ -23,6 +23,7 @@ pub struct RunArgs {
     timeout: humantime::Duration,
 
     /// Prefix to send import invocations to
+    #[arg(long, default_value = "")]
     import: String,
 
     /// Path or URL to Wasm command component
@@ -45,9 +46,11 @@ pub struct ServeArgs {
     group: Option<String>,
 
     /// Prefix to send import invocations to
+    #[arg(long, default_value = "")]
     import: String,
 
     /// Prefix to listen for export invocations on
+    #[arg(long, default_value = "")]
     export: String,
 
     /// Path or URL to Wasm command component