separate documentation

[SKairinos]

As part of our dev workflow we need to start including all documentation regarding a repo's code within that repo. All documentation should be contained within the /docs directory. This makes it possible to include docs in our PRs going forward so that when a code change happens, we also update the appropriate documentation (if necessary).

The problem is that our code-specific and non-code-specific documentation is mixed together in the same GitBook spaces. We should create at least one dedicated space per repo and sync them to that repo. All non-code-specific documentation should be in their own spaces and not synced to any repo.