Provided more tooltip detail and fixed validation when using the attachment output type.
Issue: MIRTH-2389
A new task to export a single attachment as either binary or text now exists within the MessageBrowser and shows up when an attachment is selected. This is achieved by adding in a new AttachmentExportDialog, TaskConstant and Operation to facilitate this feature. Several operations are exposed within the MessageBrowser so as to retrieve the attachment ID as well as the mime type. By modifying both the Client and MessageObjectServlet, we are able to accommodate exporting attachments within the server.

A shared AttachmentWriter utility class was added to the server project which is responsible for creating and exporting the file attachment to either the server or local file system.

DICOM is currently unsupported as an attachment type, and as such will alert the user.
Issue: MIRTH-2501