Wiki-based documentation on contribution process

cc @johanneshaertel @kevin-klein @sschauss

As discussed, we need some concise and clear description of the contribution process, even for ourselves.

As discussed, we would use the project wiki for that purpose.

The top-level README.md file and the landing page should then link to the main wiki site.

I can think of these issues needing documentation:

What is a contribution? (Code implementing features, a model for documentation)
How to submit a contribution? (Essentially by pull request, while model must be in the commit and code could be elsewhere)
What features to implement? (Link to paper, link to feature model on 101wiki).
How to discover concepts in an implementation? (Refer to the paper for the underlying data mining approach that could be applied in a simplified manner to each new contribution. That is, identify resources such as papers and apply term frequency ranking to identify key terms and see whether they are on 101wiki.
How to get write access to 101wiki? @kevin-klein: any idea what sort of protocol we should use? For now, I suggest that softlang@uni-koblenz.de as the general contact address. I guess we need some more computed-supported protocol here such as a github-authenticated user requests editing rights on 101wiki maybe by also filling in some message field. I don't know.
How to use the well-formedness checker?
Guidelines on ordering sections in a model

softlang / metalib