enhance: move segcore codes of segment into one package

[chyezh]

issue: #33285

• move most cgo opeartions related to search/query into segcore package for reusing for streamingnode.
• add go unittest for segcore operations.

[sre-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: chyezh
To complete the pull request process, please assign wxyucs after the PR has been reviewed.
You can assign the PR to them by writing /assign @wxyucs in a comment when ready.

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

Needs approval from an approver in each of these files:

• OWNERS

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

[mergify]

@chyezh go-sdk check failed, comment rerun go-sdk can trigger the job again.

[mergify]

@chyezh E2e jenkins job failed, comment /run-cpu-e2e can trigger the job again.

[codecov]

Codecov Report

Attention: Patch coverage is 81.04693% with 105 lines in your changes missing coverage. Please review.

Project coverage is 80.64%. Comparing base (00edec2) to head (9d6f946).

Files with missing lines	Patch %	Lines
internal/util/segcore/segment.go	81.77%	26 Missing and 11 partials ⚠️
internal/querynodev2/segments/segment.go	86.77%	9 Missing and 7 partials ⚠️
internal/util/segcore/requests.go	69.23%	8 Missing and 4 partials ⚠️
internal/util/segcore/reduce.go	9.09%	5 Missing and 5 partials ⚠️
internal/querynodev2/segments/collection.go	62.50%	4 Missing and 2 partials ⚠️
internal/util/segcore/collection.go	81.25%	4 Missing and 2 partials ⚠️
internal/querynodev2/segments/result.go	16.66%	4 Missing and 1 partial ⚠️
internal/querynodev2/segments/segment_l0.go	0.00%	3 Missing ⚠️
internal/util/segcore/cgo_util.go	88.46%	2 Missing and 1 partial ⚠️
internal/util/segcore/responses.go	75.00%	2 Missing and 1 partial ⚠️
... and 2 more

Additional details and impacted files

@@             Coverage Diff             @@
##           master   #37722       +/-   ##
===========================================
+ Coverage   68.91%   80.64%   +11.73%     
===========================================
  Files         290     1365     +1075     
  Lines       25471   190852   +165381     
===========================================
+ Hits        17553   153921   +136368     
- Misses       7918    31499    +23581     
- Partials        0     5432     +5432     

Components	Coverage Δ
Client	61.25% <ø> (∅)
Core	68.91% <ø> (ø)
Go	83.15% <81.04%> (∅)

Files with missing lines	Coverage Δ
internal/querynodev2/segments/cgo_util.go	28.57% <ø> (ø)
internal/querynodev2/segments/count_reducer.go	100.00% <100.00%> (ø)
internal/querynodev2/segments/reducer.go	90.90% <ø> (ø)
internal/querynodev2/segments/retrieve.go	82.40% <100.00%> (ø)
internal/querynodev2/segments/search.go	63.47% <100.00%> (ø)
internal/querynodev2/segments/segcore.go	100.00% <100.00%> (ø)
internal/querynodev2/segments/segment_loader.go	72.90% <100.00%> (ø)
internal/querynodev2/server.go	77.62% <100.00%> (ø)
internal/querynodev2/tasks/query_stream_task.go	79.16% <100.00%> (ø)
internal/querynodev2/tasks/query_task.go	90.17% <100.00%> (ø)
... and 14 more

... and 1051 files with indirect coverage changes

[mergify]

@chyezh E2e jenkins job failed, comment /run-cpu-e2e can trigger the job again.