Move In Progress ostrio-files changes to separate branch, and revert ostrio-files changes, so that:

- Export to CSV/TSV with custom fields works
- Attachments are not exported to disk
- It is possible to build arm64/s390x versions again.

Thanks to xet7 !

Related #3110

models/wekanCreator.js

@@ -415,7 +415,6 @@ export class WekanCreator {
           const self = this;
           if (Meteor.isServer) {
             if (att.url) {
-              // FIXME: Change to new file library
               file.attachData(att.url, function(error) {
                 file.boardId = boardId;
                 file.cardId = cardId;
@@ -441,7 +440,6 @@ export class WekanCreator {
                 }
               });
             } else if (att.file) {
-              // FIXME: Change to new file library
               file.attachData(
                 Buffer.from(att.file, 'base64'),
                 {