Add AWS boto3 error code exception function is_boto3_error_code (#41202)

* Add aws/core.py function to check for specific AWS error codes

* Use sys.exc_info to get exception object if it isn't passed in

* Allow catching exceptions with is_boto3_error_code

* Replace from_code with is_boto3_error_code

* Return a type that will never be raised to support stricter type comparisons in Python 3+

* Use is_boto3_error_code in aws_eks_cluster

* Add duplicate-except to ignores when using is_boto3_error_code

* Add is_boto3_error_code to module development guideline docs

lib/ansible/modules/cloud/amazon/ec2_vpc_vgw.py

@@ -116,6 +116,7 @@ try:
 except ImportError:
     HAS_BOTO3 = False
 
+from ansible.module_utils.aws.core import is_boto3_error_code
 from ansible.module_utils.aws.waiters import get_waiter
 from ansible.module_utils.basic import AnsibleModule
 from ansible.module_utils.ec2 import HAS_BOTO3, boto3_conn, ec2_argument_spec, get_aws_connection_info, AWSRetry
@@ -220,9 +221,9 @@ def create_vgw(client, module):
     except botocore.exceptions.WaiterError as e:
         module.fail_json(msg="Failed to wait for Vpn Gateway {0} to be available".format(response['VpnGateway']['VpnGatewayId']),
                          exception=traceback.format_exc())
-    except client.exceptions.from_code('VpnGatewayLimitExceeded') as e:
+    except is_boto3_error_code('VpnGatewayLimitExceeded'):
         module.fail_json(msg="Too many VPN gateways exist in this account.", exception=traceback.format_exc())
-    except botocore.exceptions.ClientError as e:
+    except botocore.exceptions.ClientError as e:  # pylint: disable=duplicate-except
         module.fail_json(msg=to_native(e), exception=traceback.format_exc())
 
     result = response