docs: move avatar docs to the Menu & Header section

Author: yaroslav8765

adminforth/documentation/docs/tutorial/03-Customization/01-branding.md

@@ -252,26 +252,4 @@ customization: {
   ]
 }
 
-```
-
-## User Avatar
-
-If you want your user to have custom avatar you can use avatarUrl function in auth section:
-
-```ts title='./index.ts'
-
-auth: {
-
-  ...
-
-  avatarUrl: async (adminUser)=> { 
-    return ... // absolute URL of avatar for this adminUser
-  },
-
-  ...
-
-}
-
-```
-
-We recommend to use this feature with [upload plugin](https://adminforth.dev/docs/tutorial/Plugins/upload/#using-plugin-for-uploading-avatar)
+```

adminforth/documentation/docs/tutorial/03-Customization/10-menuConfiguration.md

@@ -1,4 +1,4 @@
-# Menu Configuration
+# Menu & Header
 
 
 ## Icons
@@ -253,3 +253,26 @@ import adminforth from '@/adminforth';
 adminforth.menu.refreshMenuBadges()
 ```
 
+## Avatars
+
+If you want your user to have custom avatar you can use avatarUrl:
+
+```ts title='./index.ts'
+
+auth: {
+
+  ...
+
+  avatarUrl: async (adminUser)=> { 
+    return `https://${process.env.STORAGE_PROVIDER_PATH}/${adminUser.dbUser.avatar_path}`
+  },
+
+  ...
+
+}
+
+```
+
+This syntax can be use to get unique avatar for each user of hardcode avatar, but it makes more sense to use it with [upload plugin](https://adminforth.dev/docs/tutorial/Plugins/upload/#using-plugin-for-uploading-avatar)
+
+