add download to issued cert

http-api/app/routes/enrollments/download_issued_cert.py

@@ -0,0 +1,27 @@
+from aws_lambda_powertools.event_handler.api_gateway import Router
+from layercake.dynamodb import DynamoDBPersistenceLayer
+
+from boto3clients import dynamodb_client, s3_client
+from config import BUCKET_NAME, ENROLLMENT_TABLE
+
+EXPIRES_IN = 300
+
+router = Router()
+enrollment_layer = DynamoDBPersistenceLayer(ENROLLMENT_TABLE, dynamodb_client)
+
+
+@router.get('/<id>/download')
+def download(id: str):
+    params = {
+        'Bucket': BUCKET_NAME,
+        'Key': f'issuedcerts/{id}.pdf',
+        'ResponseContentDisposition': f'attachment; filename="{id}.pdf"',
+    }
+
+    return {
+        'presigned_url': s3_client.generate_presigned_url(
+            'get_object',
+            Params=params,
+            ExpiresIn=EXPIRES_IN,
+        )
+    }