[Standards] Resolve uncertainty about File Sharing Standards

Dear Council Members, For years now we have two competing standards https://xmpp.org/extensions/xep-0447.html and https://xmpp.org/extensions/xep-0385.html and it leads to confusion and additional work for new implementers and prevents in some cases implementations at all. According to the xmpp.org page both XEPs have each 6 implementations. I would suggest to issue a last call to gather feedback. After all feedback is addressed council should advances only one. Regards Philipp