pd-ctl: try to fix interactive mode (#3782)

[ti-chi-bot]

This is an automated cherry-pick of #3782

What problem does this PR solve?

Seems cobra command does not support interactive mode, that is we need to init a new command every new line in the REPL.

What is changed and how it works?

1. readlineCompleter global variables are removed, it is now inlined and created-as-need.
2. PersistentFlags from the root command will be inherited in the REPL, pd address for example.
3. Start a new command every new evaluation round.

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)

pd-ctl -i -u http://127.0.0.1:34/
store --help
store

Interactive should print normally, and show connection refused on port 34.

Release note

Fix broken interactive pd-ctl mode

[codecov]

Codecov Report

Merging #3784 (356559b) into release-5.1 (2258e38) will decrease coverage by 0.18%.
The diff coverage is 0.00%.

@@               Coverage Diff               @@
##           release-5.1    #3784      +/-   ##
===============================================
- Coverage        75.08%   74.89%   -0.19%     
===============================================
  Files              245      245              
  Lines            24531    24540       +9     
===============================================
- Hits             18418    18380      -38     
- Misses            4493     4526      +33     
- Partials          1620     1634      +14     

Flag	Coverage Δ
unittests	74.89% <0.00%> (-0.19%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
tools/pd-ctl/pdctl/ctl.go	39.63% <0.00%> (-3.50%)	⬇️
server/id/id.go	76.19% <0.00%> (-14.29%)	⬇️
server/region_syncer/server.go	83.33% <0.00%> (-6.07%)	⬇️
server/member/member.go	65.59% <0.00%> (-4.31%)	⬇️
server/statistics/hot_cache_task.go	75.00% <0.00%> (-4.17%)	⬇️
pkg/etcdutil/etcdutil.go	84.70% <0.00%> (-3.53%)	⬇️
client/base_client.go	82.47% <0.00%> (-2.58%)	⬇️
server/schedule/operator/step.go	66.77% <0.00%> (-2.33%)	⬇️
server/server.go	70.56% <0.00%> (-2.28%)	⬇️
server/schedule/checker/rule_checker.go	80.11% <0.00%> (-1.11%)	⬇️
... and 7 more

---

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 2258e38...356559b. Read the comment docs.

[nolouch]

/merge

[ti-chi-bot]

@nolouch: It seems you want to merge this PR, I will help you trigger all the tests:

/run-all-tests

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the ti-community-infra/tichi repository.

[ti-chi-bot]

@nolouch: /merge in this pull request requires 2 approval(s).

In response to this:

/merge

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the ti-community-infra/tichi repository.

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• lhy1024
• nolouch

To complete the pull request process, please ask the reviewers in the list to review by filling /cc @reviewer in the comment.
After your PR has acquired the required number of LGTMs, you can assign this pull request to the committer in the list by filling /assign @committer in the comment to help you merge this pull request.

The full list of commands accepted by this bot can be found here.

Reviewer can indicate their review by submitting an approval review.
Reviewer can cancel approval by submitting a request changes review.

[nolouch]

/merge

[ti-chi-bot]

@nolouch: It seems you want to merge this PR, I will help you trigger all the tests:

/run-all-tests

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the ti-community-infra/tichi repository.

[ti-chi-bot]

This pull request has been accepted and is ready to merge.

Commit hash: 356559b