Merge branch feature/auto-vic-ui-plugin (vmware#577)

The ui plugin install/upgrade/uninstall scripts have been reimplemented in vic-product as rest apis, the registration codes have been moved to vic-product as well. These scripts are removed.

Update Downstream product trigger from vic to vic-product to reflect the relationship change.

(cherry picked from commit 594baa3)

.drone.yml

@@ -136,7 +136,7 @@ pipeline:
     image: 'gcr.io/eminent-nation-87317/vic-downstream-trigger:1.3'
     environment:
       SHELL: /bin/bash
-      DOWNSTREAM_REPO: vmware/vic
+      DOWNSTREAM_REPO: vmware/vic-product
       DOWNSTREAM_BRANCH: ${DRONE_BRANCH}
     secrets:
       - drone_server