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/FieldUrl.jsx

@@ -0,0 +1,101 @@
+import React, {Fragment} from 'react'
+import PropTypes from 'prop-types'
+import FieldString from './FieldString'
+import SmallError from './SmallError'
+
+
+function validate (url) {
+  if (url === "") {
+    return;
+  }
+
+  let error;
+  const getProtocol = (url) => {
+    try {
+      const urlObj = new URL(url);
+      return urlObj.protocol;
+    }
+    catch (err) {
+      return undefined;
+    }
+  };
+  const protocol = getProtocol(url);
+  const isSsl = window.location.protocol === "https:";
+
+  if (!protocol) {
+    error = (
+      <SmallError>
+        Must provide protocol {
+          isSsl
+          ? <code>https://</code>
+          : <><code>http://</code> or <code>https://</code></>
+        }
+      </SmallError>
+    );
+  }
+  else if (
+    protocol &&
+    protocol === "http:" &&
+    window.location.protocol === "https:"
+  ) {
+    error = (
+      <SmallError>
+        CORS policy won&apos;t allow fetching resources served over http from https, use a <code>https://</code> domain
+      </SmallError>
+    );
+  }
+
+  return error;
+}
+
+export default class FieldUrl extends React.Component {
+  static propTypes = {
+    "data-wd-key": PropTypes.string,
+    value: PropTypes.string,
+    style: PropTypes.object,
+    default: PropTypes.string,
+    onChange: PropTypes.func,
+    onInput: PropTypes.func,
+    multi: PropTypes.bool,
+    required: PropTypes.bool,
+  }
+
+  static defaultProps = {
+    onInput: () => {},
+  }
+
+  constructor (props) {
+    super(props);
+    this.state = {
+      error: validate(props.value)
+    };
+  }
+
+  onInput = (url) => {
+    this.setState({
+      error: validate(url)
+    });
+    this.props.onInput(url);
+  }
+
+  onChange = (url) => {
+    this.setState({
+      error: validate(url)
+    });
+    this.props.onChange(url);
+  }
+
+  render () {
+    return (
+      <div>
+        <FieldString
+          {...this.props}
+          onInput={this.onInput}
+          onChange={this.onChange}
+        />
+        {this.state.error}
+      </div>
+    );
+  }
+}
+