Add collect tsdb

[nexustar]

What problem does this PR solve?

What is changed and how it works?

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)
• No code

Code changes

• Has exported function/method change
• Has exported variable/fields change
• Has interface methods change
• Has persistent data change

Side effects

• Possible performance regression
• Increased code complexity
• Breaking backward compatibility

Related changes

• Need to cherry-pick to the release branch
• Need to update the documentation

[CLAassistant]

All committers have signed the CLA.

[codecov-commenter]

Codecov Report

Base: 28.52% // Head: 30.11% // Increases project coverage by +1.59% 🎉

Coverage data is based on head (d79cd46) compared to base (b05d398).
Patch coverage: 100.00% of modified lines in pull request are covered.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #429      +/-   ##
==========================================
+ Coverage   28.52%   30.11%   +1.59%     
==========================================
  Files          52       50       -2     
  Lines        4523     4218     -305     
==========================================
- Hits         1290     1270      -20     
+ Misses       3063     2778     -285     
  Partials      170      170              

Flag	Coverage Δ
unittests	30.11% <100.00%> (+1.59%)	⬆️

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

Impacted Files	Coverage Δ
cmd/diag/command/collect.go	34.23% <100.00%> (+0.60%)	⬆️
cmd/diag/command/collectdm.go	30.77% <100.00%> (+0.67%)	⬆️
pkg/models/metadata.go
pkg/models/tidbcluster.go

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.

☔ View full report at Codecov.
📢 Do you have feedback about the report comment? Let us know in this issue.