core: set bytesUploaded/bytesTotal as soon as the file is added
core: set bytesUploaded/bytesTotal as soon as the file is added

This fixes an issue with the upload ETA sometimes being `NaN`. These
properties would be undefined when some files did not yet emit progress
events, blowing up the ETA calculation.

transloadit/uppy,transloadit/uppy,transloadit/uppy,transloadit/uppy