Hierarchy Implementation Proposal

[temmey]

Basics

• [ ] I added a line to /doc/CHANGELOG.md
• [ ] The PR is rebased with current master.
• [ ] Details of what you changed are in commit messages.
• [ ] References to issues, e.g. close #X, are in the commit messages.
• [ ] The buildserver is happy.

Checklist

• [ ] I have installed and I am using pre-commit hooks
• [ ] I fully described what my PR does in the documentation (not in the PR description)
• [ ] I fixed all affected documentation
• [ ] I fixed the introduction tour
• [ ] I wrote migrations in a way that they are compatible with already present data
• [ ] I fixed all affected decisions
• [ ] I added unit tests for my code
• [ ] I added code comments, logging, and assertions as appropriate
• [ ] I translated all strings visible to the user
• [ ] I mentioned every code or binary not directly written or done by me in reuse syntax
• [ ] I created left-over issues for things that are still to be done
• [ ] Code is conforming to our Architecture
• [ ] Code is conforming to our Guidelines (exceptions are documented)
• [ ] Code is consistent to our Design Decisions

Review

• [ ] I've tested the code
• [ ] I've read through the whole code
• [ ] Examples are well chosen and understandable