stroom-v6.0-alpha.9

* Issue **#592** : Mount stroom at /stroom.

* Issue **#608** : Fixed stream grep and stream dump tools and added
tests to ensure continued operation.

* Issue **#603** : Changed property description from `tags` to `XML
elements` in `BadTextXMLFilterReader`.

* Issue **#600** : Added debug to help diagnose cause of missing index
shards in shard list.

* Issue **#611** : Changed properties to be defined in code rather than
Spring XML.

* Issue **#605** : Added a cache for retrieving user by name to reduce
DB use when pushing users for each task.

* Issue **#610** : Added `USE INDEX (PRIMARY)` hint to data retention
select SQL to improve performance.

* Issue **#607** : Multiple improvements to the code to ensure DB
connections, prepared statements, result sets etc use try-with-resources
constructs wherever possible to ensure no DB resources are leaked. Also
all connections obtained from a data source are now returned
appropriately so that connections from pools are reused.

* Issue **#602** : Changed the data retention rule table column order.

* Issue **#606** : Added more stroom properties to tune the c3P0
connection pool. The properties are prefixed by
`stroom.db.connectionPool` and
`stroom.statistics.sql.db.connectionPool`.

* Issue **#601** : Fixed NPE generated during index shard retention
process that was caused by a shard being deleted from the DB at the same
time as the index shard retention job running.

* Issue **#609** : Add configurable regex to replace IDs in heap
histogram class names, e.g. `....$Proxy54` becomes
`....$Proxy--ID-REMOVED--`

* Issue **#570** : Refactor the heap histogram internal statistics for
the new InternalStatisticsReceiver

* Issue **#599** : DocumentServiceWriteAction was being used in the
wrong places where EntityServiceSaveAction should have been used instead
to save entities that aren't document entities.