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/advanced/backend/taxes/inclusive-pricing.md

@@ -1,3 +1,7 @@
+---
+description: 'Learn what tax-inclusive pricing is and how it works in Medusa. Tax-inclusive pricing allows merchants to set the final prices for products and shipping options regardless of what tax rate is applicable for the customer.'
+---
+
 # Tax Inclusive Pricing
 
 In this document, you’ll learn how tax-inclusive pricing works in Medusa.

docs/content/advanced/backend/taxes/manual-calculation.md

@@ -1,3 +1,8 @@
+---
+description: 'Learn how to manually calculate taxes during checkout in the Medusa server. There are different methods including using endpoints or services.'
+addHowToData: true
+---
+
 # Calculate Taxes Manually in Checkout
 
 In this document, you’ll learn how to manually calculate taxes during checkout if you have automatic tax calculation disabled in a region.