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-io]

Codecov Report

Merging #627 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #627   +/-   ##
=======================================
  Coverage   13.75%   13.75%           
=======================================
  Files          65       65           
  Lines        3641     3641           
=======================================
  Hits          501      501           
  Misses       3090     3090           
  Partials       50       50

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update f8755eb...bff9620. Read the comment docs.

[allencloud]

LGTM