[cloud] new module lambda_policy (PR #24951)

- Fixes to lambda
- reformatting + tests for lambda_facts
- lambda module integration test
- switch lambda and lambda_facts to AnsibleAwsModule
- Get the account ID from STS, GetUser, and finally error message

test/integration/targets/aws_lambda_policy/templates/endpoint-test-swagger-api.yml.j2

@@ -0,0 +1,39 @@
+---
+swagger: "2.0"
+info:
+  version: "2017-05-11T12:14:59Z"
+  title: "{{resource_prefix}}LambdaBased_API"
+host: "fakeexample.execute-api.us-east-1.amazonaws.com"
+basePath: "/lambdabased"
+schemes:
+- "https"
+paths:
+  /mini/{greet_name}:
+    get:
+      produces:
+      - "application/json"
+      parameters:
+      - name: "greet_name"
+        in: "path"
+        required: true
+        type: "string"
+      responses:
+        200:
+          description: "200 response"
+          schema:
+            $ref: "#/definitions/Empty"
+      x-amazon-apigateway-integration:
+        responses:
+          default:
+            statusCode: "200"
+        uri: "{{mini_lambda_uri}}"
+        requestTemplates:
+          application/json: "{\"statusCode\": 200}"
+        passthroughBehavior: "when_no_match"
+        httpMethod: "POST"
+        contentHandling: "CONVERT_TO_TEXT"
+        type: "aws_proxy"
+definitions:
+  Empty:
+    type: "object"
+    title: "Empty Schema"