Rename repo to something more about project KB than only proposals

[olberger]

From a discussion I've had with @Mierdin, it seems the aim of the present repo is more to gather some "knowledge base" or other reference documents about the project (other than technical documentation for the software).

So I think the name "proposals" isn't best suited given the current state (like the approved Governance doc).

My proposal is "project Knowledge Base", but I'm sure there are better options fo a new name.

Hth,