FORGEPLUGINS-159 Support date and time HTML5 input types.

This adds support for HTML5 date and time input types for the JPA
DATE and TIME Temporal types, in addition to the datetime-local
support for DATETIME Temporal type.
Fix to ensure that time values submitted have a fixed date.

This ensures that time values are measured as number of millis
since epoch, i.e. the date fragment is always Jan 1, 1970 at the
server-side.