allow decrypting keys with a passphrase

[Forum1877621]

No description provided.

[ferama]

Thanks for your work, but I'm sorry to say that at current status this pull request is not acceptable.

What needs to be improved

1. tests doesn't run correctly
2. ssh client configuration must be in sshc/conf.go and needs to be applicable to config file
3. cache package you introduced is unwanted / unneeded (there is already the config mechanism)

About the point 2, rospo can use a config file too. Using the config file rospo needs to run without user interaction. The introduction of password encrypted keys, must be supported by config file too.

[Forum1877621]

I use command line only so I don't want to spend time adding config file support, sorry
idk enough about go to know why the tests are failing in github, they work on my dev machine