Wiki pages / GitHub pages describing architecture designs/assumptions

[Cdebus]

Create some wiki pages that describe (maybe also with a couple of graphics) the concept of the HeAT design, assumptions made in tensor and MPI handling and architectural decisions.

[Cdebus]

• Split semantics
• Basic usage
• Balanced Tensors
• Using accelerators and communicators

[ClaudiaComito]

GSoC22 is the time to get this done. I'm assigning the GSoC22 mentors and will later involve the GSoC participants as well.