add dropdown menu

...0306_remove_districthomepage_menu_button_name_and_more.py

elections/blocks.py

...064_remove_electionshomepage_menu_button_name_and_more.py

main/blocks.py

...ons/0141_remove_mainhomepage_menu_button_name_and_more.py

...tions/0142_mainhomepage_popout_button_content_and_more.py

...grations/0143_alter_mainhomepage_popout_button_content.py

main/models.py

shared/models/main.py

shared/static/styleguide2/main.css

shared/static/styleguide2/main.js

...es/styleguide2/includes/organisms/layout/main/navbar.html

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

...grations/0115_alter_uniwebhomepage_menu_button_content.py

...grations/0116_alter_uniwebhomepage_menu_button_content.py

uniweb/models.py