Add example CI configurations for more CI/CD tools

[mersinvald]

Is your feature request related to a problem? Please describe. Currently we only provide info for CircleCI configuration (and in the worst possible form of the actual pipeline we use).

Describe the solution you'd like Add a separate directory examples/ci with sample configs for

• [ ] CircleCI
• [ ] TravisCI
• [ ] Drone
• [ ] GitLab CI
• [ ] Jenkins

[mandrean]

and GitHub Actions V2!