Use barrel import from @mui/material

On advice of Ryan Christian of microbundle - fixes problem
with webpack path resolution when importing into CRA - see

developit/microbundle#1023

Author: sandtreader

package.json

@@ -4,7 +4,7 @@
   "description": "Rafiki React Administration Framework",
   "keywords": ["react", "administration", "portal", "dashboard"],
   "license": "MIT",
-  "version": "0.1.9g",
+  "version": "0.1.10",
   "type": "module",
   "source": "src/rafiki.ts",
   "main": "dist/rafiki.cjs",

src/lib/Framework.tsx

@@ -6,16 +6,9 @@ import MenuStructure from './MenuStructure';
 import AuthenticationProvider from './AuthenticationProvider';
 import SessionState from './SessionState';
 
-import Container from '@mui/material/Container';
-import Box from '@mui/material/Box';
-import Drawer from '@mui/material/Drawer';
-import TextField from '@mui/material/TextField';
-import Button from '@mui/material/Button';
-import Stack from '@mui/material/Stack';
-import Alert from '@mui/material/Alert';
-import Typography from '@mui/material/Typography';
-import AppBar from '@mui/material/AppBar';
-import Toolbar from '@mui/material/Toolbar';
+import { Container, Box, Drawer, TextField, Button,
+         Stack, Alert, Typography,
+         AppBar, Toolbar } from '@mui/material';
 
 type FrameworkProps = {
   authProvider: AuthenticationProvider;

src/lib/Menu.tsx

@@ -2,14 +2,8 @@
 // Copyright (c) Paul Clark 2022
 
 import React, { useState, Dispatch, SetStateAction } from 'react';
-
-import List from '@mui/material/List';
-import ListItem from '@mui/material/ListItem';
-import ListItemButton from '@mui/material/ListItemButton';
-import ListItemIcon from '@mui/material/ListItemIcon';
-import ListItemText from '@mui/material/ListItemText';
-import Collapse from '@mui/material/Collapse';
-import Icon from '@mui/material/Icon';
+import { List, ListItem, ListItemButton, ListItemIcon,
+         ListItemText, Collapse, Icon } from '@mui/material';
 
 import MenuStructure from './MenuStructure';
 import MenuState from '../lib/MenuState';