Adds topdoc task and template for creating icon markup partials from capital framework topdoc comments.

This sets us up for converting the data stored within Capital Framework Topdoc comments into HTML partials that can be used as Jekyll includes. We will probably need a template for each ui-type since the markup for displaying it here in the design manual might be different for each type. I have only set up the icons, more templates will need to be made but let's first see if this is working out.