Add upgrade test to pipeline

[jberkhahn]

This would deploy the current version of service catalog, a broker, provision a service and binding, and then deploy the new version on top and make sure everything survives the transition.

Much of the groundwork that needs to be down for #2659 will probably be useful here.

[mszostok]

/assign

[mszostok]

The migration tool and documentation were already created:

• Provide Migration Path for Apiserver -> CRDs #2634

And here is the script for executing that tool both locally and on CI:

• https://github.com/kyma-incubator/service-catalog/blob/crds-migration/contrib/hack/ci/run-migration-tests.sh#L91-L108

Pull request to kubernetes/test-infra: (will be created after merging CRDs):

• https://github.com/kubernetes/test-infra/compare/master...mszostok:add-sc-upgrade-pipeline?expand=1

Test executed on prow:

• https://status.build.kyma-project.io/view/gcs/kyma-prow-logs/logs/post-test-sc-upgrade-job/1162329278755377152

[mszostok]

the story was successfully finished