Add ability to customize DatagridLoading

[botjaeger]

Is your feature request related to a problem? Please describe.

Describe the solution you'd like Can we add a property to customize the loading display of Datagrid like make it Skeleton or a Custom component

Describe alternatives you've considered

Additional context

[slax57]

Thank you for this suggestion.

Currently, it's doable in user-land by wrapping the <Datagrid> and using the ListContext to render a custom loading component when isLoading is true.

However it could be nice indeed to offer simpler ways to customize the default Datagrid loading component.

Let's keep this issue open for now, to see if it gains some traction from the community. It's not priority for us, so we won't work on it for now, but feel free to open a PR if you'd like!