Improve e2e tests (#1111)

* icnrease vm size

* cache deps

* switch to the absolute cache path as cdp does not support shell expansion

* do not pull non-existing image

* manually install kind

* add alias to kind

* use full kind name

* one more name change

* install kind with other tools

* add bind mounts instead of copying files

* test fetching the runner image

* build image for pierone

* bump up the client-go version to match the master

* bump up go version

* install pinned version of kind before any test run

* do not overwrite local ./manifests during test run

* update the docs

* fix kind name

* update go.* files

* fix deps

* avoid unnecessary image upload

* properly install kind

* Change network to host to make it reachable within e2e runner. May not be the right solution though.

* Small changes. Also use entrypoint vs cmd.

* Bumping spilo. Load before test.

* undo incorrect merge from the master

Co-authored-by: Sergey Dudoladov <sergey.dudoladov@zalando.de>
Co-authored-by: Jan Mußler <janm81@gmail.com>

e2e/kind-cluster-postgres-operator-e2e-tests.yaml

@@ -1,5 +1,5 @@
 kind: Cluster
-apiVersion: kind.sigs.k8s.io/v1alpha3
+apiVersion: kind.x-k8s.io/v1alpha4
 nodes:
 - role: control-plane
 - role: worker