docs: auto generate pouch cli/api docs via code

[pouchrobot]

Signed-off-by: pouchrobot [email protected]

1.Describe what this PR did
This PR is automatically done by AI-based collaborating robot.
Pouchrobot will auto-generate cli/api document via https://github.com/spf13/cobra/tree/master/doc every day.

2.Does this pull request fix one issue?
None

3.Describe how you did it
First, execute command "make client" to build new pouch cli;
Second, execute command "./pouch gen-doc" to generate new cli docs.

For API part, we use a tool swagger2markup to make it.

4.Describe how to verify it
None

5.Special notes for reviews
The cli/api doc must be automatically generated.

[codecov-io]

Codecov Report

Merging #1094 into master will decrease coverage by 0.92%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #1094      +/-   ##
==========================================
- Coverage   16.47%   15.55%   -0.93%     
==========================================
  Files         161      161              
  Lines        8921     8712     -209     
==========================================
- Hits         1470     1355     -115     
+ Misses       7347     7255      -92     
+ Partials      104      102       -2

Impacted Files	Coverage Δ
pkg/kernel/kernel.go	72.72% <0%> (-7.28%)	⬇️
pkg/utils/utils.go	80% <0%> (-2.07%)	⬇️
cli/cli.go	0% <0%> (ø)	⬆️
client/client.go	36.36% <0%> (+7.79%)	⬆️

[allencloud]

LGTM