Remove unused Accordion component (#4827)

#3467 removed `NamespaceLanding` which was the only component that imported 
`Accordion`, so we can delete the file.

Signed-off-by: Carol Scott carol@buoyant.io

web/app/js/components/util/Accordion.jsx

@@ -1,86 +0,0 @@
-import ExpandMoreIcon from '@material-ui/icons/ExpandMore';
-import ExpansionPanel from '@material-ui/core/ExpansionPanel';
-import ExpansionPanelDetails from '@material-ui/core/ExpansionPanelDetails';
-import ExpansionPanelSummary from '@material-ui/core/ExpansionPanelSummary';
-import PropTypes from 'prop-types';
-import React from 'react';
-import { withStyles } from '@material-ui/core/styles';
-
-const styles = theme => ({
-  root: {
-    width: '100%',
-  },
-  heading: {
-    fontSize: theme.typography.pxToRem(15),
-    flexBasis: '33.33%',
-    flexShrink: 0,
-  },
-  secondaryHeading: {
-    fontSize: theme.typography.pxToRem(15),
-    color: theme.palette.text.secondary,
-  },
-});
-
-class Accordion extends React.Component {
-  constructor(props) {
-    super(props);
-    this.state = {
-      expanded: props.defaultOpenPanel || null,
-    };
-  }
-
-  handlePanelSelect = panel => (_event, expanded) => {
-    const { onChange } = this.props;
-
-    this.setState({
-      expanded: expanded ? panel : false,
-    });
-
-    if (expanded) {
-      onChange(panel);
-    }
-  };
-
-  render() {
-    const { classes, panels } = this.props;
-    const { expanded } = this.state;
-
-    return (
-      <div className={classes.root}>
-        {
-          panels.map(panel => (
-            <ExpansionPanel
-              elevation={3}
-              expanded={expanded === panel.id}
-              onChange={this.handlePanelSelect(panel.id)}
-              key={panel.id}>
-              <ExpansionPanelSummary expandIcon={<ExpandMoreIcon />}>
-                {panel.header}
-              </ExpansionPanelSummary>
-              <ExpansionPanelDetails>
-                {panel.body || 'No data present.'}
-              </ExpansionPanelDetails>
-            </ExpansionPanel>
-          ))
-        }
-      </div>
-    );
-  }
-}
-
-Accordion.propTypes = {
-  defaultOpenPanel: PropTypes.string,
-  onChange: PropTypes.func.isRequired,
-  panels: PropTypes.arrayOf(PropTypes.shape({
-    id: PropTypes.string,
-    header: PropTypes.node,
-    body: PropTypes.node,
-  })),
-};
-
-Accordion.defaultProps = {
-  defaultOpenPanel: null,
-  panels: [],
-};
-
-export default withStyles(styles)(Accordion);