[DataGrid] Improve controllable sorting

[dtassone]

Part of #2044 (sorting)

// Props
- onSortModelChange?: (params: GridSortModelParams) => void;
+ onSortModelChange?: (model: GridSortModel) => void;

// Usage
- <DataGrid onSortModelChange = {(params: GridSortModelParams)=>  setSortModel(params.model)} />
+ <DataGrid onSortModelChange = {(model: GridSortModel)=> setSortModel(model) } />

[flaviendelangle]

https://github.com/mui-org/material-ui-x/blob/89faae80aa46309b231eb78d56f133615b425685/docs/pages/api-docs/data-grid/data-grid.md
https://github.com/mui-org/material-ui-x/blob/89faae80aa46309b231eb78d56f133615b425685/docs/pages/api-docs/data-grid/x-grid.md

Missing update on these two files for onSortModelChange

[m4theushw]

Most of the demos in https://deploy-preview-2095--material-ui-x.netlify.app/components/data-grid/sorting/ are broke or the sorting is locked.

[m4theushw]

Almost there.