[FR] Add md5 of file to the properties of note generated

[Feraidoon Mehri]

Currently noter notes NOTER_DOCUMENT. I want to have the md5 of the file stored as NOTER_MD5.

:PROPERTIES:
:NOTER_DOCUMENT: ../../../Base/_Books/Uni7/sheldon/sheldon ross probability cropped.pdf
:NOTER_PAGE: 320
:END: