Add sftp, ws, to AsyncIOManager

[Super-Genius]

We'll need to have some functionality to load MNN or other data from https:// websockets, ws:// and secure ftp sftp://

[itsafuu]

For clarification, do we really mean SFTP(SSH File Transfer Protocol, sometimes called Secure File Transfer Protocol), or do we mean FTPS(File Transfer Protocol Secure, using TLS)? Or we could possible do both?