enhance: [2.4] pick default root password and log level pr

[SimFG]

default root password

• issue: [Enhancement]: Enable root password configuration at startup #33058
• pr: enhance: support to config root user's password #34752

set log level

• issue: [Bug]: the log level doesn't take effect when changing it at runtime #34756
• pr: fix: make the log level can be dynamically changed at runtime #34757

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 81.13%. Comparing base (d74a5bd) to head (d85ee69).
Report is 1 commits behind head on 2.4.

Additional details and impacted files

@@            Coverage Diff             @@
##              2.4   #34777      +/-   ##
==========================================
- Coverage   81.15%   81.13%   -0.03%     
==========================================
  Files         786      786              
  Lines      112773   112871      +98     
==========================================
+ Hits        91525    91581      +56     
- Misses      16855    16889      +34     
- Partials     4393     4401       +8     

Files	Coverage Δ
internal/rootcoord/root_coord.go	91.93% <100.00%> (ø)
pkg/util/constant.go	93.33% <ø> (ø)
pkg/util/paramtable/component_param.go	98.29% <100.00%> (+0.01%)	⬆️

... and 32 files with indirect coverage changes

[xiaofan-luan]

/lgtm
/approve

[sre-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: SimFG, xiaofan-luan

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

The pull request process is described here

Needs approval from an approver in each of these files:

• cmd/OWNERS [xiaofan-luan]
• configs/OWNERS [xiaofan-luan]
• internal/distributed/OWNERS [xiaofan-luan]
• internal/rootcoord/OWNERS [xiaofan-luan]
• pkg/util/OWNERS [xiaofan-luan]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment