Split out of T219141

Acceptance Criteria

• Each form field has a label.
• Placeholders describe the intended input by an example.
• The form layout is implemented as shown in the mock.
• When interacting with form fields, the viewport is not scrolled anymore.
• Form fields are still being validated client-side and show validity indication.
• Server-side validation errors (that were not caught on the client) are displayed in the form when redisplaying the form.

Notes

• Asynchronous server-side validation can be dropped, except for bank account data and e-mail address.