Move jcli cwp into a separate plugin

[LinuxSuRen]

Is your feature request related to a problem? Please describe.
A plugin mechanism brought in from #385. And the command jcli cwp is not a core function of jcli. So it's good to move it to a separate plugin,

Describe the solution you'd like
Please consider those things before someone start to do it:

• do it after jcli v0.0.28 which means waiting the plugin mechanism released is necessary
• give users a good suggestion when they found out sub-command cwp is missing

Describe alternatives you've considered
None.

Additional context
None.