Add extension to create sqs queue policy

[ghost]

Example:

extensions:
    queuePolicy:
        Properties:
            PolicyDocument:

[fredericbarthelet]

Hi @alanjoseuk and thanks for proposing such new extension on the queue construct. Could you be a bit more descriptive of the exact use case you need to provide extension there ? As far as I understood, the current implementation does not generate any QueuePolicy, so I believe adding a brand new one in the native resources property of your service file might be sufficient. WDYT ?