Create E2E tests using Kyverno Chainsaw

[ValentinGerlach]

What would you like to be added:

Two types of E2E tests:

1. Generic cluster provider conformance tests. Those should be stored in a separate repository and can be used to validate if a cluster supports the required APIs.
2. Provider-specific tests. In this case it should check if the cluster provider is able to create a Gardener shoot (can be checked using Chainsaw's multi-cluster feature). Also, the status should be reflected in the Cluster.status property.

Why is this needed:

It should be possible to check whether the cluster provider works as expected.