Add some CI/CD system for building and testing the generator's code

[im-konge]

As every application, the generator should be build and tested with every PR that will be open to its repository.
We should pick some CI/CD system, that will do following steps:

• build the project and everything needed for testing
• test the code
• possibly push new changes to somewhere
• checkstyle

[Frawless]

Build and publish pipeline added as part of #8

[Frawless]

I think majority of the tasks mentioned above is already done. Closing this as done.