Specify sub-directory during get

[laidbackware]

Is your feature request related to a problem? Please describe.
I use Ubuntu Desktop, where the ssh-agent is managed by the gnome keychain, which only seems to auto-import ssh keys from .ssh and not any sub-directories.

Describe the solution you'd like
I'd like get to have a --directory flag (relative to .ssh), with the default set to "keys", so that I am able to tell it to not add keys to a sub-directory.

Describe alternatives you've considered
Currently I need to script moving the keys after getting them.

Explain any additional use-cases
n/a

Additional context
n/a