Add optional Help icon to nodes

[dpgraham4401]

Add an optional help icon to our nodes, preferably to our BaseNode component as this functionality is central to all nodes and it accomplishes the task in a in a DRY method.

This should be passed as an optional prop to the BaseNode component. If the prop is present, render a clickable help icon in the top-right or top-left corners of the node. The onClick functionality is TBD.

depends on

[dpgraham4401]

closing as this is a duplicate of #77 (or rather, that is a duplicate of this)