Engineer automated e2e tests

[ccremer]

Summary

As wrestic developer\ I want automated end-to-end tests\ So that I do not accidentally break use cases when adding or changing code

Context

e2e tests speed up local development and quality assurance by testing the use cases in a automated fashion. Without those, we don't know whether a code change is attached with a risk of breaking something.

Out of Scope

• List aspects that are explicitly not part of this feature

Further links

• See implementation of DETIK framework
• documented testcases

Acceptance criteria

Given a new PR\ When I want to contribute a new feature or change\ Then I can easily add a new e2e test or adapt an existing one

Given the documented testcases\ When I create a PR to close this issue\ Then I have added most of the proposed test cases automated in code

Implementation Ideas

• Setup a KIND cluster
• Install Minio with Helm in the KIND cluster
• Run the tests with make e2e_test

[ccremer]

Closing as the plan is to integrate wrestic codebase into k8up, where e2e-tests are already existing.