Add shared preferences package description (#3016)

* Added SharedPreference description

Added SharedPreference description from pub.dev

* Update content/roadmaps/117-flutter/content/109-storage/101-shared-preferences.md

Co-authored-by: Kamran Ahmed <kamranahmed.se@gmail.com>

content/roadmaps/117-flutter/content/109-storage/101-shared-preferences.md

@@ -1 +1,6 @@
-# Shared preferences
+# Shared Preferences
+
+In Flutter, SharedPreferences is a plugin allowing you to store data in key-value pairs persistently. It is similar to a local database or cache, but it is specifically designed to store small pieces of data, such as user preferences or settings. The SharedPreferences plugin is often used to store simple pieces of data that need to be accessed by multiple screens or widgets in an app. For example, you might use SharedPreferences to store the user's login status or the app's theme color.
+
+<ResourceGroupTitle>Free Content</ResourceGroupTitle>
+<BadgeLink colorScheme='yellow' badgeText='Visit' href='https://pub.dev/packages/shared_preferences'>shared_preferences - pub.dev package</BadgeLink>