New Container: sshd container with different variant `ubuntu, fedora, archlinux, ...`, with ability to preset a lot of authetication related value

What is the new container you'd like to have?

If possible just OS container like ubuntu, fedora, ...

But with sshd service enabled, and the authentication or users is preset by the provided argument to the Container class.

This class of container can significantly ease the testing process for user who are developing SSH-protocol related application.

Today, too many utility are depending on SSH protocol for secure connection (like git, rsync, sshfs, ...), especially in Unix/Linux world.

Why not just use a generic container for this?

Because sshd setup and configuration is relatively complicated, if all the time, user have to manually configure it, it will waste user a lot of time, and it is buggy especially apply it in a testing scenario.

There is different way of authentication and setting for sshd running in different distro.
If this work is done by the user, the user has to manually copy and do string editing in the configuration file for sshd. If exception arise, user will be very difficult to figure out whether the error is from their testcase or the container itself.

And SSHD is a different protocol to HTTP.

Other references:

Include any other relevant reading material about the enhancement.

• https://hub.docker.com/search?categories=Operating+Systems
• https://linux.die.net/man/8/sshd
• https://www.openssh.com/

该 issue 未指定文件或测试入口点。首先检查仓库现有的容器 API 以及链接的 OpenSSH 和 sshd 参考资料，然后定义受支持的发行版变体、身份验证输入和测试，以证明该容器已准备好用于 SSH 协议。