Upgrade americano version and handle file uploads with streams

I use multiparty middleware to handle file uploads. I use streams instead of saving file to the disk before storing it in the Data System. 

The PR is not ready to merge but I think most of the code can be reviewed.

What needs to be done:
- fix tests (after all in files failed and folder tests kept stuck).
- test if it works with the current version of the Data System (I only tested it with the Data System with upload managed via stream (see my other PR https://github.com/cozy/cozy-data-system/pull/88)

No sub function should be enought. In fact I have a problem with the part object, I don't understand in which situation it causes the pipe to be fully read. Assigning it to another variable may cause that in some situations. So we should first list the case where it happens.