Add Rate this App Dialog Prompt

[Akash-Ramjyothi]

Description:

If there was a feature to automatically prompt to directly navigate to the Playstore would be better for users to give feedback and rate this app. Unless the users absolutely love or absolutely hate the app, they're not likely to go out of their way to rate the app on the Play Store. In scenarios like these it is critical to nudge users into rating the android app.

Maybe Fixed on: #23.