plugin attachment: remove "path" from attachment once used: "path" refers to a local path of a file, we don't want to store it in database as the file may be in a temporary location, or even be a temporary file. So once the file has been uploaded, we remove it.

You'll find install instructions in documentation (see doc/installation.rst).

If you need help, come the SàT official XMPP room: sat@chat.jabberfr.org or join us with a web browser via https://chat.jabberfr.org/converse.js/sat@chat.jabberfr.org