initial design docs

Created by: vitiral

Problem: write design docs for redox

Solution: this is a first pass at developing design docs and is not in a state to be merged. The purpose of this PR is to get feedback on the overall methodology

Changes introduced by this pull request:

• adding a new design/ folder and .art folder with new design documents.

Drawbacks: no draw backs

TODOs: pretty much everything. The plan is:

• get the high level docs written to a point that they are useful and merge them
• write lowever level docs in separate (smaller) merges and link them to implementation and tests

Fixes: #844 (closed)

State: WIP

Blocking/related: none