Turn warnings into errors when building doc

Created by: martinRenou

Have the tests fail when there is a warning in the sphinx generation.

doc/source/api/force_bdss.core_plugins.dummy.dummy_data_source.rst

+force_bdss.core_plugins.dummy.dummy_data_source package
+=======================================================
+
+Submodules
+----------
+
+force_bdss.core_plugins.dummy.dummy_data_source.dummy_data_source module
+------------------------------------------------------------------------
+
+.. automodule:: force_bdss.core_plugins.dummy.dummy_data_source.dummy_data_source
+    :members:
+    :undoc-members:
+    :show-inheritance:
+
+force_bdss.core_plugins.dummy.dummy_data_source.dummy_data_source_bundle module
+-------------------------------------------------------------------------------
+
+.. automodule:: force_bdss.core_plugins.dummy.dummy_data_source.dummy_data_source_bundle
+    :members:
+    :undoc-members:
+    :show-inheritance:
+
+force_bdss.core_plugins.dummy.dummy_data_source.dummy_data_source_model module
+------------------------------------------------------------------------------
+
+.. automodule:: force_bdss.core_plugins.dummy.dummy_data_source.dummy_data_source_model
+    :members:
+    :undoc-members:
+    :show-inheritance:
+
+
+Module contents
+---------------
+
+.. automodule:: force_bdss.core_plugins.dummy.dummy_data_source
+    :members:
+    :undoc-members:
+    :show-inheritance: