feat: back to source with piece group

[jim3ma]

Description

Currently, for multiple pieces tasks, we download them by one piece for one request, download them by multiple pieces(piece group) is a better solution. This PR implements it.

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.

[codecov]

Codecov Report

Merging #2826 (1ff13bd) into main (3dc2e46) will decrease coverage by 1.11%.
Report is 57 commits behind head on main.
The diff coverage is 78.75%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2826      +/-   ##
==========================================
- Coverage   52.06%   50.95%   -1.11%     
==========================================
  Files         157      161       +4     
  Lines       21364    21989     +625     
==========================================
+ Hits        11123    11205      +82     
- Misses       9594    10126     +532     
- Partials      647      658      +11     

Flag	Coverage Δ
Object-compatibility-e2etests	?
e2etests	?
unittests	50.95% <78.75%> (-1.11%)	⬇️

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

Files	Coverage Δ
client/daemon/storage/local_storage.go	31.28% <0.00%> (ø)
client/daemon/storage/local_storage_subtask.go	26.85% <50.00%> (ø)
client/daemon/peer/piece_manager.go	48.74% <79.61%> (-4.41%)	⬇️

... and 21 files with indirect coverage changes

[gaius-qi]

LGTM

[gaius-qi]

LGTM

[xujihui1985]

LGTM