feat #199: added network change receiver

[yashraj-01]

Issue Fix

Fixes #199

Screenshots

Description

I have added a network change receiver which displays a toast message when there is no internet connection.

• [x] Run the unit tests with ./gradlew check to make sure you didn't break anything

• [x] If you have multiple commits please combine them into one commit by squashing them.

[yashraj-01]

@garvit984 @shiv07tiwari please review.

[garvit984]

@yashraj-iitr It would be good if you put some screenshots, preferably gif, showing it.

[yashraj-01]

@yashraj-iitr It would be good if you put some screenshots, preferably gif, showing it.

Done!