[docs] Move all localization documentation in a unique page

[alexfauquette]

Fix #4915

There is a localization chapter in two pages: date picker and time picker.

Having two examples is not a code duplication. They cover specific edge cases:

• date picker: needs the have a mask adapted to the local to switch between countries using yyyy/mm/dd, dd/mm/yyyy, and dd.mm.yyyy
• time picker: needs a paragraph about ampm management

I group the two examples in a single page. And since we had a lot of feedback about ampm being by default true or false I added a demo in which the dev can test how the component behaves for some locale engine.

• new page: https://deploy-preview-5072--material-ui-x.netlify.app/x/react-date-pickers/localization/#date-engine-locale
• removed date-picker section: https://mui.com/x/react-date-pickers/date-picker/#localization
• removed time-picker section: https://mui.com/x/react-date-pickers/time-picker/#localization

[mui-bot]

These are the results for the performance tests:

Test case	Unit	Min	Max	Median	Mean	σ
Filter 100k rows	ms	278.2	521	388.2	400.24	99.83
Sort 100k rows	ms	464.1	875.8	772.6	706.96	141.593
Select 100k rows	ms	159.9	251.6	187.2	192.98	34.029
Deselect 100k rows	ms	106.2	285.7	134.4	157.4	65.791

Generated by 🚫 dangerJS against 23b8217

[github-actions]

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[flaviendelangle]

The section is very clear, well done !