Scala Stream Collector: replace stream list with describe to tighten permissions

In the case where you want to use AWS roles to only grant
read/write permissions to a specific Kinesis Stream, this
change allows you to avoid using the kinesis:ListStream
action.

Instead, use kinesis:DescribeStream, which is targeted to
one specific stream and doesn't require visiblity to all
streams.

Additionally, this enables you to check whether the stream
has the status "active".