Added new page for URL library

Author: drpayyne

src/guides/v2.3/extension-dev-guide/framework/url-library.md

@@ -0,0 +1,77 @@
+---
+group: php-developer-guide
+title: URL Library
+contributor_name: Adarsh Manickam
+contributor_link: https://github.com/drpayyne
+---
+
+## Overview
+
+This URL library provides numerous utilities to work with URLs. Some of the most useful URL utilities are described below.
+
+## URL Utilities
+
+### Encoder
+
+The [`Magento\Framework\Url\EncoderInterface`]({{ site.mage2bloburl }}/{{ page.guide_version }}/lib/internal/Magento/Framework/Url/EncoderInterface.php){:target="_blank"} provides a method to `encode` the URL provided to it into a base64 format and also escapes the special charaters described in the table below.
+
+|Special Character|Encoded Value|
+|--- |--- |
+| `+` | `-` |
+| `/` | `_` |
+| `=` | `,` |
+
+### Decoder
+
+The [`Magento\Framework\Url\DecoderInterface`]({{ site.mage2bloburl }}/{{ page.guide_version }}/lib/internal/Magento/Framework/Url/DecoderInterface.php){:target="_blank"} provides a method to `decode` the base64 encoded URL provided to it and also decodes the special characters described in the table below.
+
+|Special Character|Encoded Value|
+|--- |--- |
+| `-` | `+` |
+| `_` | `/` |
+| `,` | `=` |
+
+## Usage
+
+Declare `SerializerInterface` as a [constructor dependency]({{ page.baseurl }}/extension-dev-guide/depend-inj.html) to get an instance of a serializer class.
+
+```php
+use Magento\Framework\Url\DecoderInterface;
+use Magento\Framework\Url\EncoderInterface;
+
+/**
+ * @var EncoderInterface
+ */
+private $encoder;
+
+/**
+ * @var DecoderInterface
+ */
+private $decoder;
+
+
+public function __construct(
+    EncoderInterface $encoder,
+    DecoderInterface $decoder
+) {
+  $this->encoder = $encoder;
+  $this->decoder = $decoder;
+}
+
+/**
+ * Encodes URL to base64 format and escapes special characters
+ */
+public function encodeURL($url)
+{
+  return $this->encoder->encode($url);
+}
+
+/**
+ * Decodes URL from base64 format and special characters
+ */
+public function decodeURL($encodedUrl)
+{
+  return $this->decoder->decode($encodedUrl);
+}
+...
+```