Support for SSH

The ssh configuration can be as follows:

```
# Github
Host github.com
User git
HostName github.com
IdentityFile ~/.ssh/id_rsa_gitall
ProxyCommand socat - PROXY::%h:%p,proxyport=

# Gitlab
Host gitlab.com
User git
HostName altssh.gitlab.com
Port 443
IdentityFile ~/.ssh/id_rsa_gitall
ProxyCommand socat - PROXY::%h:%p,proxyport=

```

I appreciate it if the can support edit/change .ssh/config file.

The issue names no repository file, test, or entry point. Start by tracing ProxyMan’s proxy-configuration command and any SSH handling, then compare the behavior with the supplied ~/.ssh/config example; done means the requested SSH configuration support is implemented and verified.

Written by the indexing model from the issue text.