message: Proper UX for newly scaffolded plugin
diff: import React, { FC } from 'react';
  -import Typography from '@material-ui/core/Typography';
  +import { Typography, makeStyles, Theme } from '@material-ui/core';
  +
  +import { InfoCard, Header, Page, theme } from '@spotify-backstage/core';
  +
  +const useStyles = makeStyles<Theme>(theme => ({
  + mainContentArea: {
  + overflowX: 'hidden',
  + overflowY: 'auto',
  + },
  + pageBody: {
  + padding: theme.spacing(3),
  + },
  +}));
  const ExampleComponent: FC<{}> = () => {
  - return <Typography variant="h1">Welcome to {{ id }}!</Typography>;
  + const classes = useStyles();
  + return (
  + <Page theme={theme.home}>
  + <div className={classes.mainContentArea}>
  + <Header
  + title="Welcome to {{ id }}!"
  + subtitle="Optional subtitle"
  + ></Header>
  + <div className={classes.pageBody}>
  + <Typography variant="h3" style={{ padding: '8px 0 16px 0' }}>
  + Plugin page title
  + </Typography>
  + <InfoCard title="Information card" maxWidth>
  + <Typography variant="body1">
  + All content should be wrapped in a card like this.
  + </Typography>
  + </InfoCard>
  + </div>
  + </div>
  + </Page>
  + );
  };
  export default ExampleComponent;
  