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/examples.go

@@ -449,7 +449,7 @@ var _ = Describe("Examples e2e", func() {
 	})
 
 	Describe("[Example]ClusterDns", func() {
-		It("should create pod that uses dns", func() {
+		It("should create pod that uses dns [Conformance]", func() {
 			mkpath := func(file string) string {
 				return filepath.Join(testContext.RepoRoot, "examples/cluster-dns", file)
 			}