Migrate from travis to GithubActions to use SonarCloud

[dr0i]

Originates from #352 (comment):

Run the sonarcloud check (https://sonarcloud.o/dashboard?id=org.metafacture%3Ametafacture-core)

... by GithubActions to get rid of travis. See: https://github.com/SonarSource/sonarcloud-github-action

[dr0i]

Sonarcloud check is removed by 3d01453.
Closing.