At some point uplink cli lost ability to set metadata. This change
brings back this functionality for 'cp' operation.
https://github.com/storj/storj/issues/3848
Change-Id: Ia5f60eb577fcab8a38d94730d8cdc6e0338d3b46
This changes allows fetching the file size more easily (for supported
files) in order to afterwards calculate the multipart part size
accordingly.
Change-Id: Idabba4c2ee794ee471973889f5843174a7acad35