[RFC] Move BasePath meta inside the redirectTo side effect

[fzaninotto]

The redirectTo side effect, when declared via an action meta, relies on the presence of a basePath field in the meta, too:

export const crudGetOne = (
    resource: string,
    id: Identifier,
    basePath: string,
    refresh: RefreshSideEffect = true
): CrudGetOneAction => ({
    type: CRUD_GET_ONE,
    payload: { id },
    meta: {
        resource,
        fetch: GET_ONE,
        basePath,    // <= this one is only there because of redirectTo below
        onFailure: {
            notification: {
                body: 'ra.notification.item_doesnt_exist',
                level: 'warning',
            },
            redirectTo: 'list',
            refresh,
        },
    },
});

There is no real justification for that, and it doesn't make sense. No other side effect than the redirectTo saga uses that basePath field.

As it adds special cases in the options management, I suggest we move the basePath data where in belongs, in the redirectTo side effect:

export const crudGetOne = (
    resource: string,
    id: Identifier,
    basePath: string,
    refresh: RefreshSideEffect = true
): CrudGetOneAction => ({
    type: CRUD_GET_ONE,
    payload: { id },
    meta: {
        resource,
        fetch: GET_ONE,
-       basePath,
        onFailure: {
            notification: {
                body: 'ra.notification.item_doesnt_exist',
                level: 'warning',
            },
-           redirectTo: 'list',
+           redirect: { to: 'list', basePath },
            refresh,
        },
    },
});

This is a BC for people using actions with custom side effects.

[fzaninotto]

With side effects as hooks (#3425), we no longer need to pass basePath in the metas. But we don't need to remove them either: the change is backwards compatible!