Support comma split way for S3 source prefix list

[YikaiHu]

Describe the feature you'd like
Currently the Data Transfer Hub supports using S3 prefix list file to achieve select specific source prefix lists. However users need to upload the prefix list file to the data source bucket.

This can not be achieved when the data source is not belong to the user such as a public data source.

So we need a feature that DTH can support comma split way for S3 source prefix list. Then, users can just enter the prefix list in the parameter of the task.