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 #1061 into master will decrease coverage by 0.02%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #1061      +/-   ##
==========================================
- Coverage   16.17%   16.14%   -0.03%     
==========================================
  Files         140      140              
  Lines        8557     8540      -17     
==========================================
- Hits         1384     1379       -5     
+ Misses       7070     7058      -12     
  Partials      103      103

Impacted Files	Coverage Δ
pkg/kernel/kernel.go	66.66% <0%> (-6.07%)	⬇️
client/client.go	27.27% <0%> (+4.19%)	⬆️

[allencloud]

LGTM