Travis build enhancements.

[jplucinski]

There are few issues in Travis build configuration:

• Check why sonarcloud is still related to chutch-github and create in-house account
• Use one coverage report tool - now codevall and sonarqube validates those metrics
• Do this project still need cobertura plugin

Update Maven cofinguration according to:

• https://docs.travis-ci.com/user/sonarcloud/
• https://github.com/SonarSource/sq-com_example_standard-sqscanner-travis

[toniedzwiedz]

Travis integration has been removed in favour of GitHub workflows. WTT SonarCloud (https://sonarcloud.io/organizations/wttech) is now used.

Cobertura is no longer used.

Coveralls is still used but could be removed separately.