context: OpenSlides/openslides-client#5420

wanted behaviour in plain text:
election and motion polls should be visually displayed differently they need a new field to "remember" in how they should be displayed

adidtionally the meeting settings need two new settings where you can save the new option for assignments and motion polls

Wanted behaviour in technical terms:
in poll.create there shoud be a new optional variable
onehundred_percent_base: string,
required_majority: string
backend: string,

And two new meeting settings:

motion_poll_default_required_majority: string;
assignment_poll_default_required_majority: string;

additional info:
The client can only use four different options as required mayority, I do not know if the backend wants to implement to only accept these 4 options or if it should just be a string. Please implement in own discretion, and ask question if in doubt