[#1834] Restore "jpa.entities" and jpa.mapping-file properties
[#1834] Add example to test jpa.entities
* local connections weren't closed properly and none default ones were leaked
* Fix executeQuery to get the correct connection
Merge pull request #777 from xael-fry/lighthouse-1834-patch

[#1834] Restore "jpa.entities" and jpa.mapping-file properties