Add toolbar items to automatically create markdown elements

[andy-wojciechowski]

Our editor is pretty bare bones at the moment with only the ability to switch between the markdown editor or the preview view. We should add some additional functionality that other markdown editors (i.e GitHub's editor) have which allows the ability to insert different elements like links, headers, and quotes. Also, other markdown editors allow for elements to be formatted with bold and italics as well. I was thinking we leave this issue as a place to put different toolbar items we could add to our editor to make writing markdown easier.

[GFLEMING133]

This is an excellent idea. I think the best elements to auto-insert would be

1. bolding / italics / underlining
2. A dropdown for header styling (e.g., the "#"s that change the size and bolding of text)
3. Hyperlinks
4. Vertical lines
5. Charts

This would be a good PBI for a developer with some markdown experience, but I could also see some of the more ambitious newer developers pursuing this.