Add aws_caller_facts module and use it in setup-iam.yml (#36683)

* Add aws_caller_facts module and use it in setup-iam.yml

This removes the dependency on having the command line AWS tools
installed.

test/integration/targets/aws_caller_facts/aliases

@@ -0,0 +1,2 @@
+cloud/aws
+posix/ci/cloud/group4/aws

test/integration/targets/aws_caller_facts/tasks/main.yaml

@@ -0,0 +1,14 @@
+- name: retrieve caller facts
+  aws_caller_facts:
+    region: "{{ aws_region }}"
+    aws_access_key: "{{ aws_access_key }}"
+    aws_secret_key: "{{ aws_secret_key }}"
+    security_token: "{{security_token}}"
+  register: result
+
+- name: assert correct keys are returned
+  assert:
+    that:
+      - result.account is not none
+      - result.arn is not none
+      - result.user_id is not none