Check if bank details are set if collection is allowed

[Hetti]

Do not allow saving a member profile, if Bank collection allowed is checked and the following fields are empty:

account owner
IBAN
mandate reference
Date of sigining

File to adapt:
https://github.com/Metalab/mos/blob/master/templates/members/members_details.inc

[jayssSmm]

can you be more specific? what exactly we have to do?

[Hetti]

If the following field is checked the marked fields are mandatory and need to be filled out.