initial organization of UIKit folder into groups by class hierarchy

[janek]

Fixes #

Type of change:

Motivation

Todos

• [x] Completed Todo 1
• [ ] Uncompleted Todo 2

Current behavior

Expected behavior

Screenshots:

Testing Details

Please check if the PR fulfills these requirements

• [ ] Self-review: I am confident this is the simplest and clearest way to achieve the expected behaviour
• [ ] There are no dependencies on other PRs or I have linked dependencies through Zenhub
• [ ] The commit messages are clean and understandable
• [ ] Tests for the changes have been added (for bug fixes / features)
• [ ] Code runs on all relevant platforms (if major change: screenshots attached)