Integrate GitHub Workflows for day4

[AndreasM009]

As discussed in our meeting we want to integrate GitHub Workflows in day4.
The goal is, as with Azure Pipelines, to create a staged deployment to the following environments:

• Development
• Testing

In the pull request, all necessary components are built to avoid build breaks. After a merge into the main branch, the development environment is directly deployed. After a manual check, the test environment is deployed.