Prototype visual editor for FLINT

[pimotte]

There are a couple of problems with the current flinteditor from a user perspective:

1. It's way too intimidating for the average lawyer
2. Large law texts are hard to browse and check in the sources-array
3. It's relatively hard to explore and see the structure of the full model

The idea is that this can be fixed by creating a visual editor.

MPS is a prime candidate to build such a solution on.

[pimotte]

Priorities:

• [x] Import from json action
• [x] Experiment with more visual editing
• [x] Include compliance-by-design-demo interface
• [ ] Sanity check: Is MPS free to use?

[pimotte]

Feedback Robert:

UI: meer ruimte tussen feiten name/citation ontdubbelen

Voor json schema: Explanation op sources