Replace all heading tags with semantic correct alternatives

aleksis/core/templates/core/edit_dashboard.html

aleksis/core/templates/core/group/child_groups.html

aleksis/core/templates/core/group/full.html

aleksis/core/templates/core/group/list.html

aleksis/core/templates/core/index.html

aleksis/core/templates/core/person/full.html

aleksis/core/templates/core/person/list.html

aleksis/core/templates/oauth2_provider/application_list.html

aleksis/core/templates/search/search.html

aleksis/core/templates/socialaccount/connections.html

aleksis/core/templates/two_factor/core/backup_tokens.html

aleksis/core/templates/two_factor/core/phone_register.html

aleksis/core/templates/two_factor/core/setup.html

aleksis/core/templates/two_factor/core/setup_complete.html

aleksis/core/templates/two_factor/profile/disable.html

aleksis/core/templates/two_factor/profile/profile.html