[pickers] Base UI DX for the date views

[flaviendelangle]

This is an early stage draft of what the DX could look like for the unstyled version of the date views.

Curent MUI X structure

<DateCalendar />

Edit day, month and year for a single date.

• the "year" view uses the public <YearCalendar /> component
• the "month" view uses the public <MonthCalendar /> component
• the "day" view uses the private <DayCalendar /> component

<YearCalendar />

Edit a year for a single date

<MonthCalendar /> edit a month for a single date

<DateRangeCalendar />

Edit days for a range of dates

• the "day" view uses the private <DayCalendar /> component
• the "year" and the "month" view are planned, but they probably won't use <YearCalendar /> and <MonthCalendar />

Planned Base UI X structure

• 15598

• RangeCalendar (WIP)

Benchmark

• React Aria - Calendar
• React Aria - RangeCalendar
• headless-datetimepicker
• headless-react-datepicker