Override main views and buttons styles and props using MUI themes

[Madeorsk]

Problem

Overriding React-admin defaults is cumbersome for many components, especially the most important ones: views and important actions such as <DeleteButton>.

Concrete use cases (to be implemented as stories and used for documentation):

• Make all mutations pessimistic
• Replace all button icons for a custom theme

Solution

In ra-ui-materialui there's a mechanism for that already: the theme. Although we use it for some components (see #10655), we now do it for views such as <List>, <Edit>, <Create>, <Show> and buttons that has variants such as <DeleteButton>, <UpdateButton>, <BulkDeleteButton> and <BulkUpdateButton>.

How To Test

From Storybook

View a list, detail view or button you want to test with and try to change the default theme.

export const defaultLightTheme: ThemeOptions = deepmerge(
    defaultThemeInvariants,
    {
        //...
        components: {
            //...

+           RaCreate: {
+               defaultProps: {
+                    className: 'custom-class',
+                    mutationMode: 'optimistic',
+                },
+           },
        },
    }
);

From simple example

To set the creation as undoable in every Create:

// ...
root.render(
    <React.StrictMode>
        <Admin
            authProvider={authProvider}
            dataProvider={dataProvider}
            i18nProvider={i18nProvider}
            queryClient={queryClient}
            title="Example Admin"
            layout={Layout}
+           theme={deepmerge(defaultLightTheme, {
+               components: {
+                   RaCreate: {
+                       defaultProps: {
+                           mutationMode: 'undoable',
+                       },
+                   },
+               },
+           } as ThemeOptions)}
        >
// ...

Additional Checks

• The PR targets master for a bugfix or a documentation fix, or next for a feature
• The PR includes unit tests (if not possible, describe why)
• The PR includes one or several stories (if not possible, describe why)
• The documentation is up to date

[djhi]

Awesome :)

[djhi]

I didn't expect referring to PREFIX would work here but it does. TIL 👍
We could simplify some other components I worked on.

[djhi]

😍