[docs] Make a clear difference between the license and license key

[oliviertassinari]

The issues I'm trying to solve:

1. A license is not a license key. Instead, we can distinguish an order and a license key.
2. "or later" can be confused with "or older", I think that it depends on how you consider the direction of time. Instead, we can focus on the version number, not when it was released.
3. Saying "only compatible" is not accurate. It the default behavior, but we can work around it. Instead, we can say it's the default behavior.

https://mui.com/x/advanced-components/#license-key-installation

[mui-bot]

These are the results for the performance tests:

Test case	Unit	Min	Max	Median	Mean	σ
Filter 100k rows	ms	242.1	430.3	323.6	325.6	72.44
Sort 100k rows	ms	440.9	790.5	742.7	660.76	131.468
Select 100k rows	ms	101.4	220.3	143.9	153.22	40.057
Deselect 100k rows	ms	98.1	199.8	188.6	162.4	35.307

Generated by 🚫 dangerJS against 304a7da

[github-actions]

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