Created README.md for Magento_Msrp module

Author: ProkopovVitaliy

app/code/Magento/Msrp/README.md

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+# Magento_Msrp module
+
+The Magento_Msrp module is responsible for Manufacturer’s Suggested Retail Price functionality.
+A current module provides base functional for msrp pricing rendering, configuration and calculation.
+
+## Installation
+The Magento_Msrp module creates the following attributes:
+
+Entity type - `catalog_product`.
+
+Attribute group - `Advanced Pricing`.
+
+- `msrp` - Manufacturer's Suggested Retail Price
+- `msrp_display_actual_price_type` -Display Actual Price
+
+Before disabling or uninstalling this module, note that the following modules depends on this module:
+
+- `Magento_MsrpConfigurableProduct`
+- `Magento_MsrpGroupedProduct`
+- `Magento_ConfigurableProduct`
+
+For information about a module installation in Magento 2, see [Enable or disable modules](https://devdocs.magento.com/guides/v2.4/install-gde/install/cli/install-cli-subcommands-enable.html).
+
+## Structure
+`Pricing\` - directory contains interfaces and implementation for msrp pricing calculations
+ (`\Magento\Msrp\Pricing\MsrpPriceCalculatorInterface`), price renderers 
+ and price models.
+ 
+`Pricing\Price\` - the directory contains declares msrp price model interfaces and implementations.
+
+`Pricing\Renderer\` - contains price renderers implementations.
+
+For information about a typical file structure of a module in Magento 2,
+ see [Module file structure](https://devdocs.magento.com/guides/v2.4/extension-dev-guide/build/module-file-structure.html#module-file-structure).
+ 
+## Extensibility
+ 
+ Extension developers can interact with the Magento_Msrp module. For more information about the Magento extension mechanism, see [Magento plug-ins](https://devdocs.magento.com/guides/v2.4/extension-dev-guide/plugins.html).
+
+[The Magento dependency injection mechanism](https://devdocs.magento.com/guides/v2.4/extension-dev-guide/depend-inj.html) enables you to override the functionality of the Magento_Msrp module.
+
+### Events
+
+This module observes the following event:
+
+`etc/frontend/`
+
+ - `sales_quote_collect_totals_after` in the `Magento\Msrp\Observer\Frontend\Quote\SetCanApplyMsrpObserver` file. 
+
+`etc/webapi_rest`
+ - `sales_quote_collect_totals_after` in the `Magento\Msrp\Observer\Frontend\Quote\SetCanApplyMsrpObserver` file. 
+
+`etc/webapi_soap`
+ - `sales_quote_collect_totals_after` in the `Magento\Msrp\Observer\Frontend\Quote\SetCanApplyMsrpObserver` file. 
+
+For information about an event in Magento 2, see [Events and observers](https://devdocs.magento.com/guides/v2.4/extension-dev-guide/events-and-observers.html#events).
+
+### Layouts
+
+This module introduces the following layouts:
+
+`view/base/layout` directory:
+
+- `catalog_product_prices`
+- `cms_index_index`
+
+`view/frontend/layout` directory:
+
+- `catalog_category_view`
+- `catalog_product_compare_index`
+- `catalog_product_view`
+- `catalogsearch_advanced_result`
+- `catalogsearch_result_index`
+- `checkout_cart_sidebar_total_renderers`
+- `checkout_onepage_failure`
+- `checkout_onepage_success`
+- `msrp_popup`
+- `review_product_list`
+- `wishlist_index_configure_type_downloadable`
+- `wishlist_index_index`
+- `wishlist_search_view`
+- `wishlist_shared_index`
+
+### UI components
+
+Module provides product admin form modifier: 
+
+`Magento\Msrp\Ui\DataProvider\Product\Form\Modifier\Msrp` - removes `msrp_display_actual_price_type` field from the form if config disabled else adds `validate-zero-or-greater` validation to the fild.
+
+## Additional information
+
+### Catalog attributes
+
+A current module extends `etc/catalog_attributes.xml` and provides following attributes for `quote_item` group:
+- `msrp`
+- `msrp_display_actual_price_type`
+
+### Extension Attributes
+The Magento_Msrp provides extension attributes for `Magento\Catalog\Api\Data\ProductRender\PriceInfoInterface`
+- attribute code: `msrp`
+- attribute type: `Magento\Msrp\Api\Data\ProductRender\MsrpPriceInfoInterface`