data/aws: Set 20m creation timeouts for instances

We've been hitting the default 10m timeout recently, starting around
[1].  Use the creation timeout knob [2] to wait a bit longer before
giving up on AWS.  20m matches the value we've used bumping this
timeout for other resources in 1ec2758 (data/aws/vpc/master-elb:
Bump load-balancer timeouts to 20m, 2019-08-27, openshift#2279) and previous.
There's no guarantee that 20m will be sufficient, the issue could be
due to internal AWS issues like a shortage of on-demand instances of
the requested type in the requested availability zone.  But it gives
AWS an even easier target to hit ;).

[1]: https://prow.svc.ci.openshift.org/view/gcs/origin-ci-test/pr-logs/pull/openshift_console/2708/pull-ci-openshift-console-master-e2e-aws-console-olm/8584
[2]: https://www.terraform.io/docs/providers/aws/r/instance.html#timeouts

data/data/aws/bootstrap/main.tf

@@ -144,6 +144,10 @@ resource "aws_instance" "bootstrap" {
     },
     var.tags,
   )
+
+  timeouts {
+    create = "20m"
+  }
 }
 
 resource "aws_lb_target_group_attachment" "bootstrap" {

data/data/aws/master/main.tf

@@ -125,6 +125,10 @@ resource "aws_instance" "master" {
     },
     var.tags,
   )
+
+  timeouts {
+    create = "20m"
+  }
 }
 
 resource "aws_lb_target_group_attachment" "master" {