Store CX attachments in the database instead of filesystem

Overriding the original attachmentService with a new DatabaseAttachmentServiceImpl.

Added a new column to KRNS_ATT_T and mapped it to DatabaseAttachment.

fixes rSmart/issues#244
Okay - as a practice our diffs for a commit should be as readable as possible. Please revise the commit so that only the lines changed show up in the diff.  Thanks, L