docs: improved SEO of documentation (#3117)

* docs: added description to documentation pages

* docs: added more descriptions

* docs: finished improving meta description

* docs: added searchbox structured data

* docs: added breadcrumbs structured data

* docs: added how to structured data

* docs: improved 404 page

* docs: added how-to frontmatter option

docs/content/user-guide/products/collections.mdx

@@ -1,5 +1,7 @@
 ---
 sidebar_position: 3
+description: 'This user guide explains how to manage collections on the Medusa admin. Learn how to create, edit, and delete collections.'
+addHowToData: true
 ---
 
 import UiIcon from '@site/src/components/UiIcon';

docs/content/user-guide/products/export.mdx

@@ -1,5 +1,7 @@
 ---
 sidebar_position: 4
+description: 'This user guide explains how to export a list of products on the Medusa admin.'
+addHowToData: true
 ---
 
 import UiIcon from '@site/src/components/UiIcon';

docs/content/user-guide/products/import.mdx

@@ -1,5 +1,7 @@
 ---
 sidebar_position: 5
+description: 'This user guide explains how to import a list of products into Medusa using the admin.'
+addHowToData: true
 ---
 
 import UiIcon from '@site/src/components/UiIcon';

docs/content/user-guide/products/index.mdx

@@ -1,5 +1,6 @@
 ---
 sidebar_position: 1
+description: 'Medusa admin allows merchants to manage products. Merchants can view products and collections, edit them, and more.'
 ---
 
 import UiIcon from '@site/src/components/UiIcon';

docs/content/user-guide/products/manage.mdx

@@ -1,5 +1,7 @@
 ---
 sidebar_position: 2
+description: 'This user guide explains how to manage products on the Medusa admin. Learn how to create a product, edit a product, and more.'
+addHowToData: true
 ---
 
 import UiIcon from '@site/src/components/UiIcon';