Generate coverage reports and integrate notification bot

[YashKumarVerma]

Like other projects of our organization, we must show code coverage and integrate a third party application and notification bot like codecov to show coverage status on code changes

This would

• make sure code is well tested
• help find reliability in tests
• analyze what parts need to be further tested
• calculate and display coverage percent

[YashKumarVerma]

working on it

[YashKumarVerma]

pinging for bounty triage @hereisnaman