Remove GCP KFDefs and E2E tests. (kubeflow#1237)

* Per kubeflow#1063 with 1.1 GCP will no longer use KFDef to deploy
  Kubeflow; isntead we will be using blueprints kubeflow/gcp-blueprints

  * So we remove all the GCP KFDefs

  * Cleanup the kfdef/OWNERs; remove Googlers since there are no longer
    anymore GCP configs.

* Fix kubeflow#818 - stop running E2E tests that deploy Kubeflow on every
  commit.

  * We now have unittests aimed at validating the manifests; so it
    no longer makes sense to fully deploy KF and verify its working.

    * E2E tests should now happen downstream.

    * We also need to remove the tests since we are removing GCP KFDefs on
      which they depend.

kfdef/OWNERS

@@ -1,11 +1,5 @@
-approvers:
-  - abhi-g
-  - gabrielwen
-  - Jeffwan
-  - jlewi
+approvers:  
+  - Jeffwan  
   - kkasravi
-  - krishnadurai
-  - kunmingg
-  - lluunn
-  - richardsliu
+  - krishnadurai  
   - yanniszark