Move ui-identicon -> react-identicon (#165)

* Move ui-identicon -> react-identicon

* ui-identicon import fix

* Update README package links

* Update doc sidebar links

* Adjust react-qr signatures, CHANGELOG

packages/react-identicon/README.md

@@ -0,0 +1,34 @@
+# @polkadot/react-identicon
+
+A generic identity icon that can render icons based on the theme, be it Substrate or Polkadot
+
+## Usage Examples
+
+To install the component, do `yarn add @polkadot/react-identicon`
+
+Inside a React component, you can now render any account with the associated icon -
+
+```javascript
+import Identicon from '@polkadot/react-identicon';
+
+...
+render () {
+  // address is an ss58-encoded address or publicKey (hex string or Uint8Array)
+  const { address } = this.props;
+  // size (optional) is a number, indicating the size (in pixels, 64 as default)
+  const size = 32;
+  // theme (optional), depicts the type of icon, one of
+  // 'polkadot', 'substrate' (default), 'beachball' or 'jdenticon'
+  const theme = 'polkadot';
+
+  // standard className & style props are also available
+  return (
+    <Identicon
+      value={address}
+      size={size}
+      theme={theme}
+    />
+  );
+}
+...
+```