cluster: add significant warning when --force is set for scale-in

[AstroProfundis]

What problem does this PR solve?

The argument --force for command scale-in is unsafe and ignores errors, it should only be used when the target node is already offline and impossible to connect.

However, some users might try to use scale-in --force to delete TiKV instances if it is stuck in Pending Offline status, and thus lead to broken region or data loss.

Close #1630

What is changed and how it works?

Add a significant warning sign in ASCII art to get the user fully aware, and require the user to type in "Yes, I know my data might be lost." instead of simply y/n to confirm the operation.

Also add a specific note that scale-in --force should not be used if there are any "Pending Offline" instances.

Check List

Tests

• Manual test (add detailed scripts or steps below)

Code changes

• Has exported function/method change

Related changes

• Need to cherry-pick to the release branch

Release notes:

NONE

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• nexustar

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.

[codecov-commenter]

Codecov Report

Merging #1629 (7ef1087) into master (2afffed) will increase coverage by 28.61%.
The diff coverage is 0.00%.

@@             Coverage Diff             @@
##           master    #1629       +/-   ##
===========================================
+ Coverage   15.60%   44.21%   +28.61%     
===========================================
  Files         151      292      +141     
  Lines       15225    26734    +11509     
===========================================
+ Hits         2376    11821     +9445     
- Misses      12332    13043      +711     
- Partials      517     1870     +1353     

Flag	Coverage Δ
cluster	34.93% <0.00%> (?)
dm	26.20% <0.00%> (?)
integrate	44.21% <0.00%> (+28.61%)	⬆️
playground	13.35% <0.00%> (?)
tiup	15.59% <0.00%> (-0.01%)	⬇️
unittest	∅ <ø> (∅)

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

Impacted Files	Coverage Δ
pkg/cluster/manager/scale_in.go	48.21% <0.00%> (ø)
pkg/tui/tui.go	52.11% <0.00%> (+26.30%)	⬆️
pkg/cluster/task/monitored_config.go	57.89% <0.00%> (ø)
components/dm/command/patch.go	59.09% <0.00%> (ø)
pkg/cluster/operation/systemd.go	0.00% <0.00%> (ø)
components/cluster/command/display.go	32.46% <0.00%> (ø)
pkg/cluster/task/scale_config.go	53.84% <0.00%> (ø)
pkg/cluster/manager/builder.go	76.83% <0.00%> (ø)
components/dm/ansible/import.go	0.00% <0.00%> (ø)
components/cluster/command/restart.go	43.75% <0.00%> (ø)
... and 230 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 2afffed...7ef1087. Read the comment docs.

[AstroProfundis]

/merge

[ti-chi-bot]

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

Commit hash: 7ef1087