Build contribution guidelines for DUI projects

[EiffL]

I propose to model our contributions guideline on the All Contributors specifications:
https://allcontributors.org/
This implies recognizing and advertising all contributions to a project, even ones without actual code commits.

What I'm thinking is that anyone who has contributed can be recognized as a contributor, even if they are not members. Only except if they breach the code of conduct, in which case they are banned from all DUI channels.

Contributors would be at least acknowledged in an associated paper. Based on the amount of contribution, the leads of a project could decide to offer authorship to contributors, but only up to the lower (3rd) authorship tier, as an incentive for people to become members.