Fix consistency alignment for paper-input on data table

nuxeo-input has an inconsistent visual style when compared with nuxeo-selectivity, for example. A clear example of this is when it is placed side-by-side in a nuxeo-data-table (please check screenshot).

This difference in margins, paddings and typography style makes it look misaligned when compared with other elements.

We should take into account the styles used in nuxeo-selectivity and try to align paper-input with it. Also, we should check if it matches our spacing Design Guidelines.