Make Settings > General project > Project description (optional) an markdown editor
### Problem to solve
make pasting of images possible.
### Further details
Sometimes you have some interesting images or tables, you want to paste in the description.
Having markdown with image / files upload would make that a lot easier.
### Proposal
Add the Markdown editor, we all know and love from issue creation / comments there.
### What does success look like, and how can we measure that?
* [ ] Markdown editor exists and is use at this place
* [ ] Markdown is rendered at all places where the description is used
### Links / references
issue