Run integration tests on CI

[php-coder]

• https://github.com/actions/checkout
• https://github.com/actions/setup-node
• https://github.com/mirromutth/mysql-action
• https://github.com/Harmon758/postgresql-action
• https://docs.github.com/en/actions/automating-builds-and-tests/building-and-testing-nodejs
• https://ldarren.medium.com/number-of-ways-to-setup-database-in-github-actions-2cd48df9faae
• https://ovirium.com/blog/how-to-make-mysql-work-in-your-github-actions/

[php-coder]

Idea: we can generate from a single endpoints.yaml all supported types of applications, build them into docker container, run on different ports and execute tests against all of them at the same time.

[php-coder]

Idea: use --dest-dir option (#24)

[php-coder]

After adding unit tests (#31) we should run them in CI as well.