mirror: support custom key-dir when rotate root.json

[AstroProfundis]

What problem does this PR solve?

Add --key-dir argument to mirror rotate subcommand

Check List

Tests

• Manual test (add detailed scripts or steps below)

Code changes

• Has exported function/method change

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• lucklove

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[codecov-commenter]

Codecov Report

Merging #1848 (51ddaae) into master (a1f44d7) will decrease coverage by 5.59%.
The diff coverage is 28.57%.

@@            Coverage Diff             @@
##           master    #1848      +/-   ##
==========================================
- Coverage   52.59%   47.01%   -5.59%     
==========================================
  Files         306      306              
  Lines       34975    35062      +87     
==========================================
- Hits        18395    16481    -1914     
- Misses      14418    16626    +2208     
+ Partials     2162     1955     -207     

Flag	Coverage Δ
cluster	32.08% <100.00%> (-9.01%)	⬇️
playground	12.79% <100.00%> (+0.18%)	⬆️
tiup	14.44% <35.71%> (+<0.01%)	⬆️
unittest	21.26% <13.33%> (-<0.01%)	⬇️

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

Impacted Files	Coverage Δ
pkg/repository/model/model.go	36.95% <0.00%> (-6.65%)	⬇️
cmd/mirror.go	44.56% <18.18%> (-0.38%)	⬇️
cmd/root.go	56.36% <100.00%> (ø)
components/cluster/command/root.go	46.02% <100.00%> (ø)
components/dm/command/root.go	56.50% <100.00%> (ø)
components/playground/main.go	45.06% <100.00%> (ø)
pkg/environment/env.go	59.28% <100.00%> (-1.80%)	⬇️
pkg/cluster/operation/systemd.go	0.00% <0.00%> (-75.00%)	⬇️
pkg/cluster/task/limits.go	0.00% <0.00%> (-65.22%)	⬇️
pkg/cluster/task/sysctl.go	0.00% <0.00%> (-63.64%)	⬇️
... and 72 more

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[lucklove]

LGTM

[lucklove]

/merge

[ti-chi-bot]

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

Commit hash: 51ddaae