Trigger individual PR per orga member for onboarding

[MarkusTiede]

[christiansiegel]

@MarkusTiede How about the following approach:

1. Comment out all current members (like 2c079e8)
2. Add an individual PR for every member (like Add member kullmanp #11) -> quite repetitive, but automating probably takes longer
3. Wait for checkboxes
4. Approve & merge

The PR comment for those PRs could be the following:

## Config changes proposed in this pull request
- Add <user> as member (was previously removed to perform new onboarding process)

### <user> acknowledges that
- [ ] he/she has **read and understood the [Open Source Guidelines](https://baloise.github.io/open-source/docs/arc42/)**
- [ ] he/she agrees to **act accordingly (with due dilligence) to our guidelines**
- [ ] he/she havs **no open questions** regarding the topics covered

[joachimprinzbach]

I would do this for main baloise org only and keep restrictions in the incubator organisation to a minimum.
I still miss the difference between baloise employees and external contributors in this approach.