File Input field

[mbohal]

Presently RUI does not include a file input (<input type="file" />)

This causes:

1. file inputs are not consistent with the rest of the UI
2. rendering of supporting elements such as label, helpTest, validationText is difficult

If solving point 1) would be too difficult or time consuming for now, I think it an acceptable compromise to only solve point 2). That could be achieved by simply wrapping the native file input with the required structures. Depending on the outcome it might be needed to mark the component in documentation as Labs, WIP or something similar.

In either case need to maintain all accessibility and functionality of the native input.