Support ssh config in ~/.ssh/config

[yanjiew1]

Theia currently does not support reading from the ~/.ssh/config file, requiring users to manually specify the username, hostname, and port number to connect to a remote host.

Feature Description:

It would be beneficial if Theia could support the SSH configuration file (~/.ssh/config), allowing users to connect using alias names and configure additional options directly within that file.

The "Remote - SSH" extension of VS Code already supports reading the SSH config file. VS Code appears to use the system's OpenSSH client, which reads from ~/.ssh/config by default.

Theia seems to use the ssh2 package for its SSH implementation, which is what another VS Code extension, open-remote-ssh uses. Although open-remote-ssh also uses ssh2, it supports reading the ~/.ssh/config file by using the ssh-config package to parse the configuration.