Tidy of components

- Moved all components into a single directory like nextjs
 - Made component names consistent with each other
 - Made component names consistent with their export class names
 - Added storybook for a few components with the aim to extend this further.

src/components/IconLayer.jsx

@@ -0,0 +1,33 @@
+import React from 'react'
+import PropTypes from 'prop-types'
+
+import IconLine from './IconLine.jsx'
+import IconFill from './IconFill.jsx'
+import IconSymbol from './IconSymbol.jsx'
+import IconBackground from './IconBackground.jsx'
+import IconCircle from './IconCircle.jsx'
+import IconMissing from './IconMissing.jsx'
+
+export default class IconLayer extends React.Component {
+  static propTypes = {
+    type: PropTypes.string.isRequired,
+    style: PropTypes.object,
+  }
+
+  render() {
+    const iconProps = { style: this.props.style }
+    switch(this.props.type) {
+      case 'fill-extrusion': return <IconBackground {...iconProps} />
+      case 'raster': return <IconFill {...iconProps} />
+      case 'hillshade': return <IconFill {...iconProps} />
+      case 'heatmap': return <IconFill {...iconProps} />
+      case 'fill': return <IconFill {...iconProps} />
+      case 'background': return <IconBackground {...iconProps} />
+      case 'line': return <IconLine {...iconProps} />
+      case 'symbol': return <IconSymbol {...iconProps} />
+      case 'circle': return <IconCircle {...iconProps} />
+      default: return <IconMissing {...iconProps} />
+    }
+  }
+}
+