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.

[allencloud]

LGTM

[codecov-io]

Codecov Report

Merging #2155 into master will decrease coverage by 0.07%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #2155      +/-   ##
==========================================
- Coverage   64.31%   64.24%   -0.08%     
==========================================
  Files         209      209              
  Lines       16664    16664              
==========================================
- Hits        10718    10705      -13     
- Misses       4614     4619       +5     
- Partials     1332     1340       +8

Flag	Coverage Δ
#criv1alpha1test	32.72% <ø> (-0.17%)	⬇️
#criv1alpha2test	33.36% <ø> (-0.02%)	⬇️
#integrationtest	39.24% <ø> (+0.01%)	⬆️
#unittest	23.85% <ø> (ø)	⬆️

Impacted Files	Coverage Δ
ctrd/watch.go	72.72% <0%> (-7.58%)	⬇️
ctrd/container.go	41.76% <0%> (-1.44%)	⬇️
daemon/mgr/container.go	55.89% <0%> (-0.83%)	⬇️
cri/v1alpha1/cri.go	63.02% <0%> (-0.35%)	⬇️
ctrd/image.go	77.19% <0%> (+2.19%)	⬆️
daemon/mgr/snapshot.go	94.2% <0%> (+4.34%)	⬆️