[EXAMPLES/ASIO] Renames Kconfig parameter and clarify

On ip::tcp::resolver ASIO uses service to identify the type of
connection and get the port number. LWIP can't resolve this way.

examples/protocols/asio/socks4/main/Kconfig.projbuild

@@ -6,11 +6,11 @@ menu "Example Configuration"
         help
             Address of the proxy to be used.
 
-    config EXAMPLE_PROXY_PORT
-        string "Proxy port"
+    config EXAMPLE_PROXY_SERVICE
+        string "Proxy Service Type"
         default "myport"
         help
-            Port for the proxy. Due to a limitation of lwip, must
-            be a number e.g. "1080".
+            Service type. Due to a limitation of lwip, must
+            be the port number e.g. "1080".
 
 endmenu

examples/protocols/asio/socks4/main/socks4.cpp

@@ -378,7 +378,7 @@ extern "C" void app_main(void)
 
     asio::io_context io_context;
     Http::Request request(Http::Method::GET, "www.httpbin.org", "80", "/get");
-    Socks::async_connect(io_context, CONFIG_EXAMPLE_PROXY_ADDRESS, CONFIG_EXAMPLE_PROXY_PORT, request.host(), request.service_port(),
+    Socks::async_connect(io_context, CONFIG_EXAMPLE_PROXY_ADDRESS, CONFIG_EXAMPLE_PROXY_SERVICE, request.host(), request.service_port(),
     [&request](std::shared_ptr<Connection> connection) {
         // Now we create a HTTP::Session and inject the necessary connection.
         std::make_shared<Http::Session>(connection)->send_request(request, [](std::shared_ptr<Http::Session> session, Http::Response response) {