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 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]

Codecov Report

Merging #2259 into master will increase coverage by 0.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #2259      +/-   ##
==========================================
+ Coverage   66.71%   66.72%   +0.01%     
==========================================
  Files         208      208              
  Lines       16924    16924              
==========================================
+ Hits        11291    11293       +2     
+ Misses       4269     4267       -2     
  Partials     1364     1364

Flag	Coverage Δ
#criv1alpha1test	32.71% <ø> (+0.2%)	⬆️
#criv1alpha2test	35.99% <ø> (-0.2%)	⬇️
#integrationtest	39.48% <ø> (-0.08%)	⬇️
#nodee2etest	33.43% <ø> (+0.18%)	⬆️
#unittest	23.76% <ø> (ø)	⬆️

Impacted Files	Coverage Δ
ctrd/watch.go	75.75% <0%> (-4.55%)	⬇️
daemon/mgr/snapshot.go	89.85% <0%> (-4.35%)	⬇️
daemon/logger/jsonfile/utils.go	71.54% <0%> (-1.63%)	⬇️
pkg/meta/store.go	62.5% <0%> (-1.57%)	⬇️
daemon/mgr/container_utils.go	83.13% <0%> (-1.21%)	⬇️
daemon/mgr/container.go	57.18% <0%> (-0.21%)	⬇️
cri/v1alpha2/cri_utils.go	90.62% <0%> (+0.29%)	⬆️
cri/v1alpha2/cri.go	66.71% <0%> (+0.29%)	⬆️
cri/v1alpha1/cri.go	61.79% <0%> (+0.33%)	⬆️
daemon/containerio/cri_log_file.go	88.23% <0%> (+3.92%)	⬆️
... and 2 more

[CLAassistant]

All committers have signed the CLA.

[fuweid]

LGTM