I realised that we can only select and upload 1 attachment file at a time to to the document. Will it be possible to have multiple selections and upload many files at a time instead of doing the same thing for many times?
Yes! Anything is possible 
Does it mean that we will have a patch really soon? 
@gohyc you asked if it was possible, not when
Best if you can get a freelancer to do it for you if you want it soon.
Haha. I am not in the urgent to have this yet. It is just a request from the users. I can wait till it is implemented.