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.

[allencloud]

LGTM

[codecov-io]

Codecov Report

Merging #1498 into master will increase coverage by 24.05%.
The diff coverage is n/a.

@@             Coverage Diff             @@
##           master    #1498       +/-   ##
===========================================
+ Coverage    16.5%   40.55%   +24.05%     
===========================================
  Files         210      253       +43     
  Lines       13889    16481     +2592     
===========================================
+ Hits         2292     6684     +4392     
+ Misses      11441     8940     -2501     
- Partials      156      857      +701

Impacted Files	Coverage Δ
daemon/logger/jsonfile/utils.go	70% <0%> (ø)	⬆️
apis/metrics/metrics.go	100% <0%> (ø)
storage/quota/set_diskquota.go	9.09% <0%> (ø)
cri/stream/httpstream/spdy/upgrade.go	0% <0%> (ø)
pkg/debug/debug.go	22.22% <0%> (ø)
storage/quota/quota.go	12.61% <0%> (ø)
internal/generator.go	100% <0%> (ø)
pkg/jsonstream/stream.go	64.7% <0%> (ø)
storage/volume/modules/tmpfs/tmpfs.go	16.12% <0%> (ø)
cri/stream/request_cache.go	0% <0%> (ø)
... and 112 more