Add flag '-t/--tmp-dir' for subcommand 'fetch'

[windvalley]

One of the cores of the subcommand fetch is to zip(zip command required on target host) the target files and directories into a temporary directory on target host. The default temporary directory is /tmp, you can change it by flag -t/--tmp-dir for some reason, e.g. insufficient space in default /tmp.

Plan to add flag:

-t/--tmp-dir directory of target hosts for storing temporary zip file (default /tmp/)