refactor: using barrier to initialize the source actor

[shanicky]

What's changed and what's your intention?

This PR tries to use Barrier to initialize the Source Actor, replacing the original Protobuf field

When the create source statement is executed, the source_manager spawns a loop coroutine to poll the source with the corresponding SplitEnumerator and store the result in memory.

At the end of create materialized view, stream_manager executes run_command(Command::CreateMaterializedView) to generate an AddMutation Barrier to initialize the entire DAG, and this PR tries to put the split initialization of the source actor into this Barrier.

Checklist

• I have written necessary docs and comments
• I have added necessary unit tests and integration tests
• All checks passed in ./risedev check (or alias, ./risedev c)

Refer to a related PR or issue link (optional)

[codecov]

Codecov Report

Merging #3067 (0deec99) into main (35216eb) will decrease coverage by 0.01%.
The diff coverage is 28.96%.

@@            Coverage Diff             @@
##             main    #3067      +/-   ##
==========================================
- Coverage   73.51%   73.50%   -0.02%     
==========================================
  Files         732      732              
  Lines       99469    99526      +57     
==========================================
+ Hits        73122    73153      +31     
- Misses      26347    26373      +26     

Flag	Coverage Δ
rust	73.50% <28.96%> (-0.02%)	⬇️

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

Impacted Files	Coverage Δ
.../frontend/src/optimizer/plan_node/stream_source.rs	100.00% <ø> (ø)
src/meta/src/stream/test_fragmenter.rs	99.28% <ø> (-0.01%)	⬇️
src/stream/src/from_proto/source.rs	0.00% <ø> (ø)
src/stream/src/executor/mod.rs	48.63% <7.14%> (-3.96%)	⬇️
src/meta/src/stream/source_manager.rs	19.58% <14.65%> (+5.30%)	⬆️
src/meta/src/barrier/command.rs	75.59% <60.86%> (-3.66%)	⬇️
src/meta/src/stream/stream_manager.rs	68.78% <61.90%> (+1.44%)	⬆️
src/stream/src/executor/chain.rs	90.81% <100.00%> (+0.29%)	⬆️
src/stream/src/executor/dispatch.rs	76.94% <100.00%> (+0.12%)	⬆️
src/stream/src/executor/source.rs	77.74% <100.00%> (-0.18%)	⬇️
... and 6 more

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[tabVersion]

LGTM

[yezizp2012]

LSTM!!!