LP1840782 Angular native date select & DateUtil class

LP1840782 Angular native date select & DateUtil class

Migrate <eg-date-select> implemenation from ng-bootstrap to
the browser-native <input type="date"/> element.

Create a DateUtil class to package some common date transforms, etc.

'DOB' handling in FormatService leverages the new DateUtil class for
generating a local date from Y/M/D and does so any time a simple Y/M/D
value is passed, instead of limiting to 'DOB' values.

Sandbox example expanded to demonstrate date clearing and improve
layout.

Signed-off-by: Bill Erickson <berickxx@gmail.com>