docs: auto generate pouch cli/api docs via code

[pouchrobot]

Signed-off-by: pouchrobot pouch-dev@alibaba-inc.com

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 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]

Codecov Report

Merging #2425 into master will increase coverage by 4.27%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #2425      +/-   ##
==========================================
+ Coverage   64.07%   68.34%   +4.27%     
==========================================
  Files         275      275              
  Lines       18309    18309              
==========================================
+ Hits        11731    12513     +782     
+ Misses       5292     4361     -931     
- Partials     1286     1435     +149

Flag	Coverage Δ
#criv1alpha1test	31.79% <ø> (?)
#criv1alpha2test	35.83% <ø> (+0.15%)	⬆️
#integrationtest	39.79% <ø> (-0.1%)	⬇️
#nodee2etest	33.03% <ø> (-0.13%)	⬇️
#unittest	25.49% <ø> (ø)	⬆️

Impacted Files	Coverage Δ
cri/ocicni/cni_manager.go	59.18% <0%> (-12.25%)	⬇️
daemon/mgr/system.go	67.93% <0%> (-5.35%)	⬇️
apis/server/utils.go	71.15% <0%> (-3.85%)	⬇️
daemon/containerio/container_io.go	74.86% <0%> (-1.1%)	⬇️
daemon/mgr/container_utils.go	86.07% <0%> (-0.64%)	⬇️
cri/v1alpha2/cri_utils.go	90.51% <0%> (-0.29%)	⬇️
cri/v1alpha2/cri.go	67.58% <0%> (-0.12%)	⬇️
cri/v1alpha2/cri_wrapper.go	61.2% <0%> (ø)	⬆️
daemon/mgr/container.go	60.44% <0%> (+0.42%)	⬆️
ctrd/container.go	58.33% <0%> (+0.47%)	⬆️
... and 10 more

[fuweid]

LGTM