use lazy calculation

disable "image upload blocking" on image jio save (probably it wrong)
use modified jio_putAttachment to save image:
* if attachId undefined then attachId = mimeType,sha1hashOfFile
* not save in jio storage if attach with checksumm already exist
* return attachId
* allow dataUri instead blob
use modified jio_getAttachment allow get attachment as dataUrl or
blobUrl (ooffice use blobUrl)