Add CI/CD automation to services and libraries

As a developer, I want to have an automated way to build and test the services when a new tag is released, and publish to NPM if it's a library. Moreover, I want to be notified if anything fails.

DoD:

- Investigate CI/CD automation tools: TravisCI, CircleCI and Jenkins;
- Add building and testing steps;
- Add publishing to NPM;
- Send notifications to slack;
- Generate CHANGELOG files;