feat(main): Add base theme: This is the falcon theme out of the box.

This is falcon v3.1.2

falcon/templates/_partials/stylesheets.tpl

@@ -0,0 +1,54 @@
+{**
+ * Copyright since 2007 PrestaShop SA and Contributors
+ * PrestaShop is an International Registered Trademark & Property of PrestaShop SA
+ *
+ * NOTICE OF LICENSE
+ *
+ * This source file is subject to the Academic Free License 3.0 (AFL-3.0)
+ * that is bundled with this package in the file LICENSE.md.
+ * It is also available through the world-wide-web at this URL:
+ * https://opensource.org/licenses/AFL-3.0
+ * If you did not receive a copy of the license and are unable to
+ * obtain it through the world-wide-web, please send an email
+ * to license@prestashop.com so we can send you a copy immediately.
+ *
+ * DISCLAIMER
+ *
+ * Do not edit or add to this file if you wish to upgrade PrestaShop to newer
+ * versions in the future. If you wish to customize PrestaShop for your
+ * needs please refer to https://devdocs.prestashop.com/ for more information.
+ *
+ * @author    PrestaShop SA and Contributors <contact@prestashop.com>
+ * @copyright Since 2007 PrestaShop SA and Contributors
+ * @license   https://opensource.org/licenses/AFL-3.0 Academic Free License 3.0 (AFL-3.0)
+ *}
+
+{$cssAssetHash = Configuration::get('PS_CCCCSS_VERSION')|md5}
+
+{foreach $stylesheets.external as $stylesheet}
+  {$url = {appendParamToUrl url=$stylesheet.uri key=v value=$cssAssetHash}}
+
+  {if $preloadCss|default:false &&
+      ($stylesheet.id === 'theme-ccc')
+      ||
+      (in_array($stylesheet.id, ['theme-main', 'theme-product', 'theme-listing', 'theme-checkout']) && $stylesheet.server !== 'remote')
+    }
+    <link
+      rel="preload"
+      href="{appendParamToUrl url=$stylesheet.uri key=v value=$cssAssetHash}"
+      as="style"
+    >
+  {/if}
+
+  <link
+    rel="stylesheet"
+    href="{appendParamToUrl url=$stylesheet.uri key=v value=$cssAssetHash}"
+    type="text/css"
+    media="{$stylesheet.media}">
+{/foreach}
+
+{foreach $stylesheets.inline as $stylesheet}
+  <style>
+    {$stylesheet.content}
+  </style>
+{/foreach}