specify custom path for public keys

[NBRAYKO]

Running into this issue

On windows local_key() looks for the public and private keys in the wrong place. By default, they are stored in C:/users/USERNAME/.ssh, whereas the home dir ~ is set to C:/users/USERNAME/Documents.

Modifying local_key() so that a custom path to the directory can be set is a better solution than recreating or copying the keys in a new place.