Initial input for the creation of formal specification documents

[jimmarino]

@ssteinbuss @PeterKoen-MSFT @sebbader Here is the initial PR for specification document input. It focuses on the Information Model and Catalog Service as a start, with contract negotiation and transfer to follow.

Note that I merged conflicts, which can make the commit history a bit messy. We can also rebase commits if that is easier.

[ssteinbuss]

This is now continued in the Dataspace Protocol specification see https://github.com/International-Data-Spaces-Association/ids-specification