Implement ticket password feature in dl-cli.py

[egcmi]

Add ticket password generation using secrets module

Enable ticket password generation in configuration file by setting ticket_pass=TRUE. ticket_pass value must be boolean. the generated token will be printed to the console

[wavexx]

This breaks the output interface though. $(dl-cli <something>) would now produce 2 lines, depending on config which would make scripting ugly.

I would prefer that the password is provided externally instead, via stdin or input file for example, like rsync does. This would still work very well with shell scripts, for example when using "pwgen" gives you full control:

umask 077
pwgen -1 > pass
dl-cli --password-file pass <file to upload>

Handling "--password-file=-" would be a bonus, but we do have /dev/stdin for this anyway. If you run dl-cli as a subprocess, stdin avoids the need to create temporary files entirely and is secure.