TypedTimePicker & TypedDateTimePicker - fix format

[glebfox]

See TODOs

Investigation

DateTimePicker and TimePicker do not have methods for setting time formats like:

setFormat(String) // setFormat("hh:mm:ss")

Vaadin suggests to use two methods to change format in TimePicker:

timePicker.setStep(Duration.ofSeconds(1)); // to use format with seconds
timePicker.setLocale(Locale.GERMANY); // to show 24 hours

And in DateTimePicker:

DatePicker.DatePickerI18n datePickerI18n = new DatePicker.DatePickerI18n();
datePickerI18n.setDateFormat("MM/dd/yyyy");

dateTimeField.setDatePickerI18n(datePickerI18n); // custom date format
dateTimeField.setStep(Duration.ofSeconds(1)); // to use format with seconds
dateTimeField.setLocale(Locale.GERMANY); // to use 24h format

Internal setI18n() method does not allow you providing methods for formatting and parsing custom format.

Vaadin has issues:

• TimePicker https://github.com/vaadin/flow-components/issues/1068
• DateTimePicker https://github.com/vaadin/flow-components/issues/3721
• DateTimePicker https://github.com/vaadin/flow-components/issues/2417

[gorbunkov]

We're waiting for vaadin fixes

[syncro]

@glebfox we had request from community for seconds to be displayed in timepicker that is currently looks unavailable