Refactor package and executable attribute handling in rosystem template

Author: ipa-rwu

templates/rossystem.rossystem.j2

@@ -2,9 +2,11 @@
   nodes:
   {% set collected = namespace(pub=[], sub=[], srv_server=[], srv_client=[], action_server=[], action_client=[]) %}
   {% for node in model.nodes %}
-    {% set pkg = node.package if node.package else 'TODO' %}
+    {% set pkg_attr = node|attr('package') %}
+    {% set pkg = pkg_attr if pkg_attr is not undefined and pkg_attr else 'TODO' %}
     {% set node_identifier = node.name.full_name.lstrip('/') %}
-    {% set exec_name = node_identifier.lstrip('/') if node_identifier else '' %}
+    {% set exec_attr = node|attr('executable') %}
+    {% set exec_name = exec_attr if exec_attr is not undefined and exec_attr else (node_identifier.lstrip('/') if node_identifier else '') %}
     {% if exec_name == '' %}
       {% set exec_name = node_identifier %}
     {% endif %}