[Regression] It's not possible to upload new files with the attachments macro anymore

[lucaa]

Starting with Pro macros 1.8, the attachments macro does not have the option to allow upload of new files anymore, as it did on version 1.6.

The upload also used to be enabled by default. Now the parameter does not even exist anymore.

[lucaa]

This change was made as part of the work of compatibility with recent versions done for ticket #112, see the comment for PR #123 .