Replace Travis CI process with GitHub Actions

[Sancretor]

Is your feature request related to a problem? Please describe.

As of now, the project uses Travis CI to implement its CI process.
But Travis CI workers are limited in free plan, and we are limited in some functionalities.
In order to improve our processes, we would like to use GitHub Actions instead.

Describe the solution you'd like

The CI/CD process should consists in these steps :

• Checkout code, build, tests, and analyze quality with SonarCloud

• If it's a push on master branch :

  • Check if a milestone is completed (nb issues > 0, nb closed issues > 0, nb open issues = 0)
  • If any, close it
  • Then create a tag and a GitHub Release with issues from this milestone, depending on labels
  • Add the generated JAR file in the Release