add more default configuration to sphinx conf.py

Add values extracted from package.xml to the wrapping sphinx config.py. This eliminates the need for packages with custom config.py to duplicate author, copyright and version information from package.xml.

rosdoc2/verbs/build/builders/sphinx_builder.py

@@ -12,6 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import datetime
 import json
 import logging
 import os
@@ -72,6 +73,10 @@ def ensure_global(name, default):
 
 ensure_global('rosdoc2_settings', {{}})
 ensure_global('extensions', [])
+ensure_global('project', "{package_name}")
+ensure_global('copyright', "{year}, {package_licenses}")
+ensure_global('author', "{package_authors}")
+ensure_global('release', "{package.version}")
 
 if rosdoc2_settings.get('enable_autodoc', True):
     print('[rosdoc2] enabling autodoc', file=sys.stderr)
@@ -643,7 +648,13 @@ def generate_wrapping_rosdoc2_sphinx_project_into_directory(
             'user_conf_py_filename': esc_backslash(
                 os.path.abspath(os.path.join(user_sourcedir, 'conf.py'))),
             'breathe_projects': ',\n'.join(breathe_projects) + '\n    ',
-            'intersphinx_mapping_extensions': ',\n        '.join(intersphinx_mapping_extensions)
+            'intersphinx_mapping_extensions': ',\n        '.join(intersphinx_mapping_extensions),
+            'year': datetime.date.today().year,
+            'package_licenses': ', '.join(package.licenses),
+            'package_authors': ', '.join(set(
+                [a.name for a in package.authors] + [m.name for m in package.maintainers]
+            )),
+            'package': package,
         }
 
         print(os.path.abspath(os.path.join(directory, 'conf.py')))