Adds the -DateKind parameter to the ConvertFrom-Json that allows the
caller to control how DateTime strings are converted into an object. The
default behaviour is to create a DateTime value with the Kind being
Unspecified if no TZ is set, Utc if the TZ Z is set, Local (after
conversion) if an explicit TZ is set. This adds a Utc, Local to
explicitly set the Kind as desired as well as a Offset and String value
to create a DateTimeOffset or keep as a string.