widgets.DateInputWidget Align design with WikimediaUI

widgets.DateInputWidget Align design with WikimediaUI

Aligning DateInputWidget with WikimediaUI theme widgets by:
- using “Red50” color `#d33` from color palette,
- using standard dialog `box-shadow` value,
- ensure handle appearance is similar to standard TextInputWidget,
- align variable name,
- introduce similar variables from WikimediaUI theme, and also
- removing unnecessary properties.
Adding a `max-height` to address vendor specific UI elements for
`type=date` in Chrome.

Bug: T180094
Change-Id: I4e0ca6c472e2d6ddbe64eb783acf8c38c5beacc4