Improve Content Editing and Evidence fields in Control Editing Form

[JJediny]

I performed a test using some of our FY19 audit requests.

• The create control form could be improved by providing a Markdown editor (e.g. https://simplemde.com/) for the Implementation narrative field.
• The Evidence field looks to be a placeholder for an upload/attach feature, but this should just be a text box or another markdown field as all I wanted to use it for was to paste a url to a google drive folder.