Add support to pre-load images in KubeSphere cluster

[LinuxSuRen]

Some images will be loaded during the runtime instead of the installation phase of KubeSphere. It's very reasonable. But for the users, might need to wait for a while before all the necessary images are ready. Case 2, users might want to use KubeSphere in a private environment which means there's no internet.

So what I want to propose is that provide a command to pre-load all necessary images as the need to the target environment.

For the machine which can access the internet, the usage could be ks images load --components devops

For no internet case, the usage could be ks images save --components devops, then load them by offline mode.

How to get the whole images list

You can get the list from file images-list.txt

One question is that it does not tell us the relation between images and components. I guess re-org the file from .txt to .yaml will be better.