Compact logging format for LoggingMetricPublisher

### Describe the feature

This is a feature request to introduce a more compact [`LoggingMetricPublisher.Format`](https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/metrics/LoggingMetricPublisher.Format.html) for [`LoggingMetricPublisher`](https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/metrics/LoggingMetricPublisher.html).

The two available options today, `PLAIN` and `PRETTY` produce a lot of text that can be costly for storage if producing a lot of logs.

For example, the `PLAIN` option has a lot of redundanct, unnecessary information such as the class names (`MetricCollecition`), and repeating `name` and `value`.

We should introduce a third format, `COMPACT` that aims to be more compact but still human readable.

### Use Case

Emitting metrics to logs in a more cost effective way.

### Proposed Solution

_No response_

### Other Information

_No response_

### Acknowledgements

- [ ] I may be able to implement this feature request
- [ ] This feature might incur a breaking change

### AWS Java SDK version used

2.x

### JDK version used

N/A

### Operating System and version

N/A

Parti da LoggingMetricPublisher e dalla sua Format API annidata, quindi segui i percorsi di output PLAIN e PRETTY esistenti. Confronta i relativi output per determinare quali informazioni possono essere rimosse mantenendo il risultato leggibile per le persone; il lavoro è completato quando è disponibile un terzo formato COMPACT che produce log delle metriche sostanzialmente più brevi.

Scritto dal modello di indicizzazione a partire dal testo della issue.