Create a CI pipeline which performs tests and release (if manually approved)

[lolski]

Scope of the CI pipeline:

1. tests:
   1. runs unit tests
   2. runs a deployment test which deploys the artifact to test.pypi.org
   3. runs an end-to-end test which verifies if the deployed artifact can be used
2. a manual approval prompt which should trigger a release process
3. release:
   1. deploy to pypi.org
   2. deploy a release draft to Githubb