[Automate] Use GitHub Actions to automating testing, quality analysis and code/test coverage when new commits or pull requests are received

[tommens]

In order to ensure that the code available in this GitHub repository remains of high quality, the workflow should be automated by using GitHub Actions (reusable actions found on the GitHub Marketplace can be used for that purpose https://github.com/marketplace). The current version already contains partial support for some of this, but needs to be improved further.

• Continuous building and testing: Whenever a new pull request or commit is being made, the unit tests and BDD tests need to be run, and a report should be generated. A pull request cannot be merged and closed as long as there remain failing tests.
• Continuous coverage and quality analysis: For every new code addition, code/test coverage and code quality checkers should be run and report their results.
• Continuous reporting: Whenever a new release is published a report needs to be generated and associated as an asset to the release. The report should contain: the full JavaDoc documentation; the full results of the tests having been executed (the release should fail if some tests do not pass); the full results of the code and test coverage analysis; the full results of the quality analysis.
• The three workflows above should be separated, and the latter two workflows should only be run conditional to the success of the first workflow.