mui-x [pickers] Support slots on the `DateField` component

Which slots do these components have

Slots of single input fields

Components: DateField, soon to come TimeField and DateTimeField, SingleInputDateRangeField

In theory, this component has no HTML tag of its own, it just calls the input with some custom props. This input can for instance be a TextField which already has 2 wrapping div (one in TextField and one in InputBase).

I see 3 possible approaches:

Root + Input: Add a not very useful div around this input just to have a Root slot and name the slot holding the TextField Input (like described in #4484)
Input: Don't add any div and name the slot holder the TextField Input (like described in #4484)
Root: Don't add any div and name the slot holder the TextField Root. This is the most rigorous for the slot nomenclature of the component but it's very incoherent with the multi input fields. I think we would loose our users if we start to name slots with the same concept differently depending on the component holding them. It would be a nightmare to document.

Slots of multi input fields

Components: MultiInputDateRangeField

Root
Input (used for both the start and end input but users can use the callback for of componentsProps to customize differently the two, this will need to be documented)
Separator

Sep 06 '22 16:09 flaviendelangle

These are the results for the performance tests:

Test case	Unit	Min	Max	Median	Mean	σ
Filter 100k rows	ms	501.9	1,001.9	626.2	749.3	188.049
Sort 100k rows	ms	545.1	1,107.1	545.1	892.46	205.456
Select 100k rows	ms	169	307.7	269	255.44	46.916
Deselect 100k rows	ms	113.4	290.6	201.2	210.96	59.996

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