fix(job): support config sync peer task batch size

[CooooolFrog]

Description

This PR addresses the Redis big key issue caused by SyncPeerJob when there are too many peers.

Related Issue

#4379

Motivation and Context

Dragonfly uses this library (https://github.com/RichardKnop/machinery) as a distributed task processor. This framework uses Redis as a task queue to store job requests and execution results (e.g. key JobResultId, value PeerHostInfos). The reason for big key problem in Redis is that the task result stores information for all peers.

I saw the group task scheduling in the machinery library, so I plan to split a job into multiple sub-jobs for execution. This would reduce the number of PeerHostInfo entries stored in a single sub-job, thus solving the big key problem.

Screenshots (if appropriate)

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation Update (if none of the other choices apply)

Checklist

• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.

[codecov]

Codecov Report

❌ Patch coverage is 6.89655% with 54 lines in your changes missing coverage. Please review.
✅ Project coverage is 28.07%. Comparing base (07054a5) to head (bcf97b2).
⚠️ Report is 35 commits behind head on main.

Files with missing lines	Patch %	Lines
manager/job/sync_peers.go	0.00%	30 Missing ⚠️
scheduler/job/job.go	0.00%	24 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4654      +/-   ##
==========================================
- Coverage   28.66%   28.07%   -0.59%     
==========================================
  Files         231      232       +1     
  Lines       23052    23141      +89     
==========================================
- Hits         6607     6496     -111     
- Misses      15983    16204     +221     
+ Partials      462      441      -21     

Flag	Coverage Δ
unittests	28.07% <6.89%> (-0.59%)	⬇️

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

Files with missing lines	Coverage Δ
manager/config/config.go	96.11% <100.00%> (+0.28%)	⬆️
scheduler/job/job.go	0.00% <0.00%> (ø)
manager/job/sync_peers.go	0.00% <0.00%> (ø)

... and 3 files with indirect coverage changes

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