[WIP] Integration test on GitHub Actions workflow

[lhelwerd]

Draft to investigate the porting of the Jenkins CI integration tests of the visualizations to GitHub Actions.

• Initial work to use GitHub CI environment variables.
• Look into configuration (secret files?) and/or ensure default configuration works properly
• Consider different ways to obtain the other visualizations, such as using NPM modules (but needs work to publish those first and then use those in the containers)
• Other simplifications in the test setup (reducing number of containers, since no production environment actually used such complex setups)
• Result collection/publication
• Security dependency checks
• Badges etc.