cluster/test-deploy/aws/OWNERS: Use installer aliases

The previous content was copy/pasted into this repo with 49f60b7
(cluster/test-deploy/aws/OWNERS: Delegate to openshift/installer,
2018-08-27, openshift#1290).  But with upstream OWNERS_ALIASES being slurped
since e1f993f (populate-owners: Also slurp OWNERS_ALIASES,
2018-08-25, openshift#1285) and the installer repo defining aliases since
openshift/installer@62f87acb (OWNERS_ALIASES: Define aliases for
reviewers and approvers, 2018-08-24, openshift/installer#184), we can
DRY this up by using the upstream aliases.

Author: wking

cluster/test-deploy/aws/OWNERS

@@ -1,11 +1,6 @@
 # See the OWNERS docs: https://git.k8s.io/community/contributors/guide/owners.md
 
 approvers:
-  - aaronlevy
-  - abhinavdahiya
-  - crawford
-  - smarterclayton
-  - wking
-  - yifan-gu
+  - installer-approvers
 reviewers:
-  - vikramsk
+  - installer-reviewers