Declare license for unique module that uses BSD-2

Co-authored-by: Maxwell G <maxwell@gtmx.me>

awx_collection/tools/roles/template_galaxy/templates/galaxy.yml.j2

@@ -19,6 +19,8 @@ homepage: https://www.ansible.com/
 issues: https://github.com/ansible/awx/issues?q=is%3Aissue+label%3Acomponent%3Aawx_collection
 license:
   - GPL-3.0-or-later
+  # plugins/module_utils/tower_legacy.py
+  - BSD-2-Clause
 name: {{ collection_package }}
 namespace: {{ collection_namespace }}
 readme: README.md