Re-implement Kinesis source without fs2-kinesis

The common-streams Kinesis source suffers from a problem where we don't
quite achieve at-least-once processing semantics near the end of a
shard. The problem was in the 3rd-party fs-kinesis library, and it is
not easy to fix with any small code change to that library.

Sorry I cannot provide a link here to back that up -- it is documented
internally at Snowplow.

This PR re-implements our Kinesis source from scratch, this time without
a dependency on fs2-kinesis.  The biggest difference is the way we block
the `shardEnded` method of the KCL record processor, until all records
from the shard have been written to the destination.

modules/it/src/test/scala/com/snowplowanalytics/snowplow/sources/kinesis/Utils.scala

@@ -12,8 +12,6 @@ import cats.effect.{IO, Ref}
 import scala.concurrent.duration.FiniteDuration
 import scala.jdk.CollectionConverters._
 
-import eu.timepit.refined.types.numeric.PosInt
-
 import software.amazon.awssdk.core.SdkBytes
 import software.amazon.awssdk.regions.Region
 import software.amazon.awssdk.services.kinesis.KinesisAsyncClient
@@ -94,7 +92,6 @@ object Utils {
     UUID.randomUUID.toString,
     KinesisSourceConfig.InitialPosition.TrimHorizon,
     KinesisSourceConfig.Retrieval.Polling(1),
-    PosInt.unsafeFrom(1),
     Some(endpoint),
     Some(endpoint),
     Some(endpoint),

modules/kinesis/src/main/resources/reference.conf

@@ -9,7 +9,6 @@ snowplow.defaults: {
         type: "Polling"
         maxRecords: 1000
       }
-      bufferSize: 1
       leaseDuration: "10 seconds"
     }
   }