Add support for per-query metrics in Hibernate statistics

[jfougere]

Current implementation of HibernateMetrics exposed counters & also time gauges for max execution queries, however no tags are provided in order to know about which query those metrics are related.

I believe this could be very useful and could be done using current Hibernate Statistics class implementation.

For example the TimeGauge hibernate.query.executions.max could be tag with a query tag and the value could be provided by Statistics.getQueryExecutionMaxTimeQueryString().

Also the other counter metrics could be retrieved by query using:

• Statistics.getQueries()
• Statistics.getQueryStatistics(String query)

What do u think ?

[jkschneider]

Sounds great. A PR would be welcome!