cubicweb-file #2983436 attribute to store checksum of file content [validation pending]

Use for example sha1.hexdigest and call it sha1hex.

prioritynormal
typeenhancement
done in1.14.0
load0.100
load left0.000
closed by#b3d6cac93948 add attribute sha1hex to store checksum (sha1.hexdigest) of file (closes #2983436)
patchadd attribute sha1hex to store checksum (sha1.hexdigest) of file (closes #2983436) [applied]