add progress bar for local file transfers

[svenrademakers]

acceptance criteria

• [ ] the tpi tool polls on a regular interval /bmc/api?type=flash&op=get and writes the bytes_written attribute to a progress bar.
• [ ] after the bmcd is finished in transfer state, the tpi tool polls the same end-point and waits until it sees a "Done" or an "error" state
• [ ] if the transfer resulted in an error, the error gets printed to the user