Explore writng a specialized summarizer for bulk ingest

To debug a recent bulk ingest test I wrote the following summarizer. This summarizer counted the number of times each UUID was seen. I used to count the number of entries each map reduce job had created.

```java
package test.ci;

import org.apache.accumulo.core.client.summary.CountingSummarizer;

public class CiUuidSummarizer extends CountingSummarizer{

@Override
protected Converter converter() {
return (k,v,c) -> c.accept(v.toString().split(":")[0]);
}

}

```

Start by reading the recent bulk ingest test that motivated the CiUuidSummarizer example and the Accumulo CountingSummarizer entry point. Clarify which summarization behavior is required, then define the implementation and test criteria; the issue currently does not specify what done looks like.

Vom Indexierungsmodell aus dem Issue-Text verfasst.