shared: Remove outdated shared Person model

district/migrations/0031_auto_20220114_1527.py

district/models.py

region/migrations/0008_auto_20220114_1527.py

region/models.py

shared/migrations/0002_delete_person.py

shared/models.py

shared/templates/shared/person_badge_snippet.html

shared/templates/shared/person_badge_wide_snippet.html

shared/wagtail_hooks.py