ci-operator/templates/openshift/installer/cluster-launch-installer-*: Random AWS regions for IPI

I'm leaving the UPI templates and such alone for now, because they
mention regions in more places and I don't care as much about them ;).
The approach mirrors what we did for Azure with 4d08a9d
(ci-operator/templates/openshift/installer/cluster-launch-installer-*:
Random Azure regions, 2019-09-18, #5081).  This should reduce resource
contention (both for limits and for API throttling) in CI.  We could
theoretically raise our Boskos caps as well, but I'm leaving that off
for now because we're getting hammered by AMI-copy issues [1].

I've also added ZONE_* variables in case we need to dodge broken zones
like we have in the past with e8921c3
(ci-operator/templates/openshift: Get e2e-aws out of us-east-1b,
2019-03-22, #3204).  I have nothing against the other us-east-1 zones
at the moment, the current ZONE_* overrides there are just to
demonstrate the idea in case folks need to pivot later.  Without
explicit ZONE_* choices, we'll fall back to using zones a and b within
the chosen region.

The DevProductivity Platform (DPP) folks bumped our quotas in the new
regions back in 2019-11 [2].  We should be good for up to 25% of our
current us-east-1 capacity in those regions.  Increases beyond that,
or sharding into additional regions, will require additional DPP <->
AWS work to get limits raised.

[1]: https://bugzilla.redhat.com/show_bug.cgi?id=1752370#c3
[2]: https://issues.redhat.com/browse/DPP-3108

Author: wking

ci-operator/templates/openshift/installer/cluster-launch-installer-e2e.yaml

@@ -347,8 +347,6 @@ objects:
       env:
       - name: AWS_SHARED_CREDENTIALS_FILE
         value: /etc/openshift-installer/.awscred
-      - name: AWS_REGION
-        value: us-east-1
       - name: AZURE_AUTH_LOCATION
         value: /etc/openshift-installer/osServicePrincipal.json
       - name: GCP_REGION
@@ -442,6 +440,16 @@ objects:
             elif has_variant "large"; then
               master_type=m5.4xlarge
             fi
+            case $((RANDOM % 4)) in
+            0) AWS_REGION=us-east-1
+               ZONE_1=us-east-1b
+               ZONE_2=us-east-1c;;
+            1) AWS_REGION=us-east-2;;
+            2) AWS_REGION=us-west-1;;
+            3) AWS_REGION=us-west-2;;
+            *) echo >&2 "invalid AWS region index"; exit 1;;
+            esac
+            echo "AWS region: ${AWS_REGION} (zones: ${ZONE_1:-${AWS_REGION}a} ${ZONE_2:-${AWS_REGION}b})"
             subnets="[]"
             if has_variant "shared-vpc"; then
               case $((RANDOM % 4)) in
@@ -465,20 +473,20 @@ objects:
             aws:
               type: ${master_type}
               zones:
-              - us-east-1a
-              - us-east-1b
+              - ${ZONE_1:-${AWS_REGION}a}
+              - ${ZONE_2:-${AWS_REGION}b}
         compute:
         - name: worker
           replicas: ${workers}
           platform:
             aws:
               type: m4.xlarge
               zones:
-              - us-east-1a
-              - us-east-1b
+              - ${ZONE_1:-${AWS_REGION}a}
+              - ${ZONE_2:-${AWS_REGION}b}
         platform:
           aws:
-            region:       ${AWS_REGION}
+            region: ${AWS_REGION}
             userTags:
               expirationDate: ${EXPIRATION_DATE}
             subnets: ${subnets}

ci-operator/templates/openshift/installer/cluster-launch-installer-src.yaml

@@ -205,8 +205,6 @@ objects:
       env:
       - name: AWS_SHARED_CREDENTIALS_FILE
         value: /etc/openshift-installer/.awscred
-      - name: AWS_REGION
-        value: us-east-1
       - name: AZURE_AUTH_LOCATION
         value: /etc/openshift-installer/osServicePrincipal.json
       - name: GCP_REGION
@@ -292,6 +290,16 @@ objects:
             elif [[ "${CLUSTER_VARIANT}" =~ "large" ]]; then
               master_type=m5.4xlarge
             fi
+            case $((RANDOM % 4)) in
+            0) AWS_REGION=us-east-1
+               ZONE_1=us-east-1b
+               ZONE_2=us-east-1c;;
+            1) AWS_REGION=us-east-2;;
+            2) AWS_REGION=us-west-1;;
+            3) AWS_REGION=us-west-2;;
+            *) echo >&2 "invalid AWS region index"; exit 1;;
+            esac
+            echo "AWS region: ${AWS_REGION} (zones: ${ZONE_1:-${AWS_REGION}a} ${ZONE_2:-${AWS_REGION}b})"
             subnets="[]"
             if [[ "${CLUSTER_VARIANT}" =~ "shared-vpc" ]]; then
               case $((RANDOM % 4)) in
@@ -315,20 +323,20 @@ objects:
             aws:
               type: ${master_type}
               zones:
-              - us-east-1a
-              - us-east-1b
+              - ${ZONE_1:-${AWS_REGION}a}
+              - ${ZONE_2:-${AWS_REGION}b}
         compute:
         - name: worker
           replicas: ${workers}
           platform:
             aws:
               type: m4.xlarge
               zones:
-              - us-east-1a
-              - us-east-1b
+              - ${ZONE_1:-${AWS_REGION}a}
+              - ${ZONE_2:-${AWS_REGION}b}
         platform:
           aws:
-            region:       ${AWS_REGION}
+            region: ${AWS_REGION}
             userTags:
               expirationDate: ${EXPIRATION_DATE}
             subnets: ${subnets}