enhance: move streaming coord from datacoord to rootcoord

[chyezh]

issue: #38399
pr: #39007

We want to support broadcast operation for both streaming and msgstream.
But msgstream can be only sent message from rootcoord and proxy.
So this pr move the streamingcoord to rootcoord to make easier implementation.

[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 87.60331% with 15 lines in your changes missing coverage. Please review.

Project coverage is 81.06%. Comparing base (e6dd3e5) to head (9ff7e5b).
Report is 3 commits behind head on 2.5.

Files with missing lines	Patch %	Lines
internal/distributed/rootcoord/service.go	50.00%	4 Missing and 2 partials ⚠️
internal/streamingcoord/server/server.go	83.33%	4 Missing and 1 partial ⚠️
internal/rootcoord/root_coord.go	84.00%	3 Missing and 1 partial ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##              2.5   #39009       +/-   ##
===========================================
+ Coverage   69.45%   81.06%   +11.61%     
===========================================
  Files         294     1384     +1090     
  Lines       26419   195536   +169117     
===========================================
+ Hits        18349   158518   +140169     
- Misses       8070    31444    +23374     
- Partials        0     5574     +5574     

Components	Coverage Δ
Client	78.26% <ø> (∅)
Core	69.46% <ø> (+0.01%)	⬆️
Go	83.05% <87.60%> (∅)

Files with missing lines	Coverage Δ
internal/coordinator/coordclient/registry.go	92.20% <100.00%> (ø)
internal/datacoord/server.go	73.20% <ø> (ø)
internal/distributed/datacoord/service.go	88.51% <ø> (ø)
internal/streamingcoord/client/client.go	96.72% <100.00%> (ø)
...al/streamingcoord/server/balancer/balancer_impl.go	77.22% <100.00%> (ø)
internal/streamingcoord/server/builder.go	100.00% <100.00%> (ø)
...nternal/streamingcoord/server/resource/resource.go	95.55% <100.00%> (ø)
...nal/streamingcoord/server/resource/test_utility.go	100.00% <100.00%> (ø)
...ngcoord/server/service/discover/discover_server.go	96.07% <100.00%> (ø)
...amingutil/service/discoverer/session_discoverer.go	82.94% <100.00%> (ø)
... and 6 more

... and 1075 files with indirect coverage changes

[mergify]

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

[chyezh]

/run-cpu-e2e

[jaime0815]

/lgtm

[sre-ci-robot]

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