Add IIS configuration to getting started guide section (#13712) [skip ci]

Supposing configurations for IIS to host Yii2 application. The reference of the code is the following question's answer on Stack Overflow:
http://stackoverflow.com/questions/30470618/iis-and-yii2-pretty-url

docs/guide/start-installation.md

@@ -290,3 +290,30 @@ in order to avoid many unnecessary system `stat()` calls.
 
 Also note that when running an HTTPS server, you need to add `fastcgi_param HTTPS on;` so that Yii
 can properly detect if a connection is secure.
+
+### IIS Configuration <span id="iis-configuration"></span>
+
+It's recommended to host the application in a virtual host where document root points to `path/to/app/web` folder. In that `web` folder you have to place a file named `web.config` i.e. `path/to/app/web/web.config`. Content of the file should be the following:
+
+```xml
+<?xml version="1.0" encoding="UTF-8"?>
+<configuration>
+<system.webServer>
+<directoryBrowse enabled="false" />
+  <rewrite>
+    <rules>
+      <rule name="Hide Yii Index" stopProcessing="true">
+        <match url="." ignoreCase="false" />
+        <conditions>
+        <add input="{REQUEST_FILENAME}" matchType="IsFile" 
+              ignoreCase="false" negate="true" />
+        <add input="{REQUEST_FILENAME}" matchType="IsDirectory" 
+              ignoreCase="false" negate="true" />
+        </conditions>
+        <action type="Rewrite" url="index.php" appendQueryString="true" />
+      </rule> 
+    </rules>
+  </rewrite>
+</system.webServer>
+</configuration>
+```