Give proper support for different types of assignment codes

On the competitor's own overview page, all types of possible assignments are written https://www.competitiongroups.com/competitions/RoskildeForAlle2022/persons/1

However, it lacks two kinds of (somewhat easy) supports.
1: For assignment codes, if there is a 'staff-' prefix, this should not be displayed. If the assignment code is listed as 'staff-runningJudge' it would be displayed as exactly that, where it would make sense to simply write 'runningJudge'.

2: On the activity overview (https://www.competitiongroups.com/competitions/RoskildeForAlle2022/activities/20), the other types of assignment codes are not listed. It should be as simple as making the same kind of header as for all the other assignments and list the people under it.

Comece pelas páginas de visão geral de concorrentes e visão geral de atividades vinculadas na issue e, em seguida, rastreie como os códigos de atribuição e os cabeçalhos de atribuição são renderizados. A tarefa estará concluída quando o prefixo `staff-` for removido dos códigos exibidos e cada tipo de código de atribuição, com suas respectivas pessoas, for mostrado na visão geral de atividades.

Escrita pelo modelo de indexação a partir do texto da issue.