Provide fixtures containing description of where the various parts of `[module/session]_results_[dct/df]` come from

[smarie]

This could be named [module/session]_results_meta_[dct/df] and could contain

• for the dictionary version, a dictionary where the key is the property name (from properties in [module/session]_results_[dct/df]) and the value is a metadata dictionary (at least I think of one metadata right now named source or kind

• for the dataframe version, a dataframe where the index is the information name, and the columns are the pieces of metadata (at least for now a single column source and kind)