Generating PDFs with JasperReport

This is to add support to generate reports on the server using JasperReports.

One Jasper report will receive one GG-CE "root entity". Let's take OrderRequest as an example.

The Jasper report file/code will be stored in the file repository in path reports/OrderRequest with name packinglist.???. The admin may upload additional report "templates" to this folder or update existing ones.

API updates

1. Extend CRUDController with GET /report/list to get the list of report templates stored in the file repository for this entity. The method returns List<RepositoryFile>.
2. Extend CRUDController with POST /report/generate/{reportTemplate} that receives the name of the Jasper report (in file repository) and a set of entity Long ids from the client. The service will load the list of entities (in a read-only transaction) and return the PDF generated by Jasper for the provided entities.