Adjustments Community CV

done

• added ODM2/GFZ Hydrology community data (fixture) and adjusted others
• extended initial_data with ODM2/GFZ Hydrology community data that is not in root
• tagging functionality to allow for fast vocabulary tagging (Community)
• customized site header, title and welcome sign via jazzmin
• checked filters
• add a Readme on how to use the admin interface (please adjust if required)

to do

• include fixtures (default_community_data.json, hydro_community_data) in gfz gitlab_ci file (done for ufz)