fix navbar scrolling bg setting, change date → timestamp and keep date property

district/migrations/0124_alter_districtarticlepage_date.py

...rations/0125_rename_date_districtarticlepage_timestamp.py

elections/migrations/0012_alter_electionsarticlepage_date.py

...ations/0013_rename_date_electionsarticlepage_timestamp.py

elections/models.py

...21/migrations/0056_alter_elections2021articlepage_date.py

...ns/0057_rename_date_elections2021articlepage_timestamp.py

elections2021/models.py

main/migrations/0070_alter_mainarticlepage_date.py

.../migrations/0071_rename_date_mainarticlepage_timestamp.py

main/models.py

shared/models/base.py

shared/models/main.py

shared/static/styleguide2/main.css

shared/static/styleguide2/main.js

...mplates/styleguide2/includes/organisms/layout/navbar.html

uniweb/migrations/0052_alter_uniwebarticlepage_date.py

...igrations/0053_rename_date_uniwebarticlepage_timestamp.py