add some district homepage blocks, prepare migrations

district/blocks.py

...ions/0128_alter_districtcalendarpage_calendar_and_more.py

...rations/0129_rename_content_districthomepage_content_2.py

...130_rename_subheader_districthomepage_content_and_more.py

district/migrations/0131_migrate_headers.py

district/migrations/0132_alter_districthomepage_content.py

district/migrations/0133_alter_districthomepage_content.py

district/migrations/0134_auto_20240508_1333.py

district/migrations/0135_alter_districthomepage_content.py

...migrations/0136_remove_districthomepage_articles_title.py

district/migrations/0137_alter_districthomepage_content.py

district/models.py

district/templates/district/district_home_page.html

...tions/migrations/0026_alter_electionshomepage_calendar.py

elections/migrations/0027_alter_electionshomepage_content.py

...grations/0060_alter_elections2021calendarpage_calendar.py

main/migrations/0081_alter_mainpersonpage_calendar.py

main/migrations/0082_alter_mainhomepage_content.py

...n/migrations/0014_alter_senatcampaignhomepage_calendar.py

shared/blocks/main.py