kubecm switch should display more items

[hellojukay]

By default, the kubecm switch command only displays options for 4 clusters. Even on a laptop, this seems rather few as there is still a large amount of empty space on the screen. I suggest that when executing the kubecm switch command, the program should clear the screen (move the cursor to the top - left corner of the screen) and then display at least 10 items of information.

[sunny0826]

This is an excellent proposal. Would you consider implementing this feature?

[hellojukay]

@sunny0826 I have implemented the above requirements, showing all options in a full-screen terminal and restoring the terminal after exiting. Thank you for your openness and tolerance, and you are welcome to give me valuable suggestions for my PR.