feat: create the ATOM feed class model, all atom feeds are instances of this class

It provides the appropriate namespace mapping, property alternate xpath selector maps that are
appropriate for parsing atom feeds

Author: Harrison Ifeanyichukwu

src/Feeds/ATOMFeed.php

@@ -0,0 +1,51 @@
+<?php
+declare(strict_types = 1);
+
+namespace Forensic\FeedParser\Feeds;
+
+use Forensic\FeedParser\Enums\FeedTypes;
+use Forensic\FeedParser\XPath;
+use Forensic\FeedParser\FeedItems\ATOMFeedItem;
+
+class ATOMFeed extends BaseFeed
+{
+    public function __construct(XPath $xpath, string $default_lang,
+        bool $remove_styles, bool $remove_scripts)
+    {
+        $namespaces = [
+            'atom' => 'http://www.w3.org/2005/Atom',
+            'xml' => 'http://www.w3.org/XML/1998/namespace'
+        ];
+
+        $property_selectors = [
+            'id' => 'atom:id',
+            'title' => 'atom:title', // text construct
+            'link' => 'atom:link[@rel="alternate"]/@href || atom:link/@href',
+            'description' => 'atom:subtitle', // text construct
+            'image' => [
+                'src' => 'atom:logo',
+                'link' => 'atom:link',
+                'title' => 'atom:title'
+            ],
+            'copyright' => 'atom:rights',
+            'publisher' => 'atom:contributor || atom:title',
+            'lastUpdated' => 'atom:updated',
+            'creator' => 'atom:generator',
+            'language' => '@xml:lang',
+            'category' => 'atom:category'
+        ];
+
+        $items_selector = 'atom:entry';
+
+        parent::__construct(
+            new FeedTypes(FeedTypes::ATOM_FEED),
+            $default_lang,
+            $xpath,
+            $namespaces,
+            $property_selectors,
+            $items_selector,
+            $remove_styles,
+            $remove_scripts
+        );
+    }
+}