`<Markdown` supports textLength property

- `<Markdown` supports `basic` attribute that limits what markdown is allowed
- `<MarkdownField` supports `basicMarkdown` property

- Removed unused imports and variables
- Fixed whitespace

- With non-relative imports

- Fixed unchecked dataset.description.substring call
- Login form works on Enter

- Use MarkdownField in forms!

- /administrator-dasboard --> /dashboard
- /descriptor/{UUID} --> /descriptor/{UUID}/edit
- /descriptor/details/{UUID} --> /descriptor/{UUID}
- /datasets/{UUID} --> /datasets/{UUID}/edit + steps
- /datasets/details/{UUID} --> /datasets/{UUID}