Run Unit & Integration Tests in CI

[zainfathoni]

Background

Thanks to our fellow contributors, we managed to work for multiple streams in parallel.
Unfortunately, our end-to-end test cannot test the upstream works without the downstream elements implemented, e.g. it couldn't test the database schema and operations without the form implementation.

Therefore, It's time to introduce a proper unit and integration tests infrastructure.

Implementation Model

You can refer to this PR as an example: kawalcovid19/wargabantuwarga.com#358.
It requires #33 as a prerequisite.

Tasks

• Run the test:coverage script in CI, call the check Unit and integration tests
• Upload the code coverage reports to Codecov
• Configure the branch protection rules to include the unit tests and Codecov checks.