Tag conformance tests with a [Conformance] string in the description

- remove skip list from conformance-test.sh and filter by the new tag
- remove experimental api tests from conformance test suite
- remove all tests from conformance test suite which are either
  restricted to e.g. gce, gke, aws or require SSH

test/e2e/downwardapi_volume.go

@@ -28,7 +28,7 @@ import (
 var _ = Describe("Downward API volume", func() {
 	f := NewFramework("downward-api")
 
-	It("should provide labels and annotations files", func() {
+	It("should provide labels and annotations files [Conformance]", func() {
 		podName := "metadata-volume-" + string(util.NewUUID())
 		pod := &api.Pod{
 			ObjectMeta: api.ObjectMeta{