Implement date-range widget date format features.

[vellengs]

PR Checklist

Please check if your PR fulfills the following requirements:

• The commit message follows our guidelines: https://github.com/cipchk/nz-schema-form/blob/master/CONTRIBUTING.md#commit
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

[x ] Bugfix
[ ] Feature
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no api changes)
[ ] Build related changes
[ ] CI related changes
[ ] Documentation content changes
[ ] Application (the showcase website) / infrastructure changes
[ ] Other... Please describe:

What is the current behavior?

https://github.com/cipchk/nz-schema-form/issues/45
Issue Number: 45

What is the new behavior?

To format value depend on schema type;

Does this PR introduce a breaking change?

[x ] Yes
[ ] No

Other information