refactor publisher and make excel files consistent

compendium_v2/background_task/__init__.py

compendium_v2/conversion/conversion.py

compendium_v2/publishers/db_publisher.py

compendium_v2/publishers/excel_parser.py

compendium_v2/publishers/excel_publisher.py

compendium_v2/resources/2021_Organisation_DataSeries.xlsx

compendium_v2/resources/2022_Connected_Users_DataSeries.xlsx

compendium_v2/resources/2022_Networks_DataSeries.xlsx

...m_v2/resources/NREN-Services-prefills_2023_Recovered.xlsx

test/test_excel_publisher.py