docs(config) Optimization portableRecords doc (#2456)

* document `optimization.portableRecords`
* Fixes #1968 🎉 🎉 🎉

Author: EugeneHlushko

src/content/configuration/optimization.md

@@ -382,3 +382,22 @@ module.exports = {
   }
 };
 ```
+
+## `optimization.portableRecords`
+
+`bool`
+
+`optimization.portableRecords` tells webpack to generate records with relative paths to be able to move the context folder.
+
+By default `optimization.portableRecords` is disabled. Automatically enabled if at least one of the records options provided to webpack config: [`recordsPath`](/configuration/other-options/#recordspath), [`recordsInputPath`](/configuration/other-options/#recordsinputpath), [`recordsOutputPath`](/configuration/other-options/#recordsoutputpath).
+
+__webpack.config.js__
+
+```js
+module.exports = {
+  //...
+  optimization: {
+    portableRecords: true
+  }
+};
+```