chore: update concurrent for some logic

[starnop]

Signed-off-by: yuxing.lyx [email protected]

Describe what this PR does / why we need it

We need to be more explicit about when we should use concurrency, and when using concurrency actually increases our chances of making mistakes. In this PR, I update these things:

1. set the concurrency of pull image is set to 1 because the bottleneck of downloading images is often in the network rather than computing resources
2. copy the registry to other master nodes, we will copy lots of small files and the bottleneck of copy registry is not in the network so we can copy multi nodes concurrently

Does this pull request fix one issue?

Describe how you did it

Describe how to verify it

Special notes for reviews

[codecov-commenter]

Codecov Report

Base: 17.56% // Head: 17.55% // Decreases project coverage by -0.01% ⚠️

Coverage data is based on head (ed0bd2e) compared to base (bc97de4).
Patch coverage: 0.00% of modified lines in pull request are covered.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1928      +/-   ##
==========================================
- Coverage   17.56%   17.55%   -0.02%     
==========================================
  Files         103      103              
  Lines        9113     9120       +7     
==========================================
  Hits         1601     1601              
- Misses       7299     7306       +7     
  Partials      213      213              

Impacted Files	Coverage Δ
pkg/image/save/save.go	0.00% <ø> (ø)
pkg/imagedistributor/scp_distributor.go	0.00% <0.00%> (ø)
pkg/ipvs/ipvs.go	79.66% <0.00%> (ø)

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[kakaZhou719]

LGTM