docs: add chapter for search-engine-optimized routes

docs/concepts/search-engine-optimization.md

@@ -39,3 +39,23 @@ It is also possible to use translation keys here.
 
 [`seo.effects.ts`](../../src/app/extensions/seo/store/seo/seo.effects.ts) is the central place for customizations concerning dynamic content, e.g. names of products or categories (asynchronous data from the API).
 Effects are an essential part of our [State Management](./state-management.md).
+
+## Optimized URLs
+
+Optimized URLs are a major factor in determining search engine rankings. They should have a clear structure and must be readable.
+By default, product, category and content page routes contain their localized context path.
+Parameters are appended to theses paths that contain localization-independent and uniquely identifiable data.
+
+| Type         | Structure                                | Parameter                                         | Example                                                                                                 |
+| ------------ | ---------------------------------------- | ------------------------------------------------- | ------------------------------------------------------------------------------------------------------- |
+| category     | complete category path                   | **-ctg**: category id                             | /computers/notebooks-and-pcs/notebook-accessories-ctgComputers.1835.1284                                |
+| product      | complete category path with product name | **-prd**: product sku, </br>**-ctg**: category id | /computers/notebooks-and-pcs/notebook-accessories/kensington-keyfolio-prd5981602-ctgComputers.1835.1284 |
+| content page | complete content page path               | **-pg**: content page id                          | /help/faq/seo/how-to-pghow-to-seo                                                                       |
+
+**_NOTE:_** The given parameters for each url are needed to differentiate category, product and content page routes.
+It is important to ensure that no identifier contains the specified parameter id.
+For example, a category name including a `-ctg` substring could lead to unwanted behavior.
+
+**_NOTE:_** Route generation and parsing for category, product and content-page routes can be customized.
+This will require changes to the well documented [`product.route.ts`](../../src/app/core/routing/product/product.route.ts), [`category.route.ts`](../../src/app/core/routing/category/category.route.ts) or [`content-page.route.ts`](../../src/app/core/routing/content-page/content-page.route.ts) files.
+Additionally, the corresponding pipes (e.g. [`product-route.pipe.ts`](../../src/app/core/routing/product/product-route.pipe.ts)) might have to be updated to fit your needs as will [`routing.ts`](../../src/app/core/utils/routing.ts).