problem: can't edit markdown

[gsovereignty]

When logging a problem, we can't edit markdown in the one page description

Solution:

implement the carta markdown editor. Use the github example https://beartocode.github.io/carta/examples

If the window size is large enough, always show a preview on the right hand side. If it is not large enough, use the preview tab like the github example.

Inside the preview, use the existing ProblemView component.