Resolve "Expose unique ID for files"

Closes #61 and #60

See merge request !43

Resolve "Enable creation of empty datasets"

Closes #94

See merge request !42

for datafile

hashed files

uploaded. Don't delete file on disc unless it is the only DataFile pointing to
it.

Adds listing of files shared with user

Closes #92

See merge request !41

Resolve "Expose download dataset link (share link)"

Closes #90

See merge request !40

Resolve "Download file annotation (json/tsv) button"

Closes #87

See merge request !39

Merge branch '78-add-possibility-to-provide-a-json-file-containing-the-annotations-of-the-various-files' into 'master'

Resolve "Add possibility to provide a .json file as annotation"

Closes #78

See merge request !38

Merge branch '70-upload-files-form-show-uploaded-files-on-return-from-form-validation-with-error' into 'master'

Resolve "Upload files form : Show uploaded files on return from form validation with error"

Closes #70

See merge request !37

Merge branch 'master' into '70-upload-files-form-show-uploaded-files-on-return-from-form-validation-with-error'

# Conflicts:
#   portal/templates/portal/secure/user/datafile_list.html