Use custom widgets for form fields that need to be rendered with custom html

[dekkers]

We currently have a lot of logic in the templates to render form fields. The html to render form fields shouldn't be in the general templates, but should be in widgets (https://docs.djangoproject.com/en/4.1/ref/forms/widgets/).

It might also be a good idea to move widgets that are general rendering of Manon components and not specific to OpenKAT to something like a django-manon package.

[underdarknl]

Agreed! See also: https://github.com/minvws/nl-kat-coordination/issues/349