improve logging for dummy selector and adapt its launch files

launch/dummy_selector.launch

 <launch>
-    <node pkg="ccf_immersive_sorting" type="dummy_selection_provider" name="my_dummy_selection_provider" output="screen"/>
+    <arg name="autoselect" default="true" />
+    <arg name="prefix" default="selector" />
+    <node pkg="ccf_immersive_sorting" type="dummy_selection_provider" name="my_dummy_selection_provider" output="screen">
+        <param name="autoselect" type="bool" value="$(arg autoselect)" />
+        <param name="prefix" type="string" value="$(arg prefix)" />
+    </node>
 </launch>

launch/dummy_selector_manual.launch

+<launch>
+    <arg name="autoselect" default="false" />
+    <arg name="prefix" default="selector" />
+    <node pkg="ccf_immersive_sorting" type="dummy_selection_provider" name="my_dummy_selection_provider" output="screen">
+        <param name="autoselect" type="bool" value="$(arg autoselect)" />
+        <param name="prefix" type="string" value="$(arg prefix)" />
+    </node>
+</launch>

src/dummy_selection_provider.cpp

@@ -28,6 +28,7 @@ nng_socket sock;
 int rv;
 
 void sendSelection(const std::string &object) {
+    ROS_INFO_STREAM("Selecting random object: " << object);
     Selection selection;
     selection.set_id(object);
     int length = selection.ByteSize();
@@ -145,7 +146,6 @@ int main(int argc, char **argv) {
                     pause_rate.sleep();
                     std::string object{objects[distribution(rng)]};
 
-                    ROS_INFO_STREAM("Selecting random object: " << object);
                     sendSelection(object);
 
                     // wait again, then send the bin object