feat: implement StatPersistentCachePeerRequest and StatPersistentCacheTaskRequest for persistent cache

[gaius-qi]

Description

Related Issue

Motivation and Context

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.

[chlins]

lgtm

[codecov]

Codecov Report

Attention: Patch coverage is 33.50785% with 127 lines in your changes missing coverage. Please review.

Project coverage is 35.47%. Comparing base (eb4e101) to head (7740d94).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
scheduler/service/service_v2.go	32.76%	116 Missing and 3 partials ⚠️
scheduler/resource/persistentcache/peer_manager.go	0.00%	7 Missing ⚠️
scheduler/scheduler.go	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3603      +/-   ##
==========================================
- Coverage   35.57%   35.47%   -0.10%     
==========================================
  Files         339      339              
  Lines       37190    37308     +118     
==========================================
+ Hits        13231    13236       +5     
- Misses      23120    23233     +113     
  Partials      839      839              

Flag	Coverage Δ
unittests	35.47% <33.50%> (-0.10%)	⬇️

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

Files with missing lines	Coverage Δ
scheduler/resource/persistentcache/host.go	0.00% <ø> (ø)
scheduler/resource/persistentcache/peer.go	0.00% <ø> (ø)
scheduler/rpcserver/rpcserver.go	100.00% <100.00%> (ø)
scheduler/rpcserver/scheduler_server_v2.go	1.26% <100.00%> (ø)
scheduler/service/service_v1.go	79.10% <100.00%> (ø)
scheduler/scheduler.go	0.00% <0.00%> (ø)
scheduler/resource/persistentcache/peer_manager.go	0.00% <0.00%> (ø)
scheduler/service/service_v2.go	65.58% <32.76%> (-6.58%)	⬇️

... and 1 file with indirect coverage changes