chore: rename rust -> src

[skyzh]

What's changed and what's your intention?

As title

Checklist

• I have written necessary docs and comments
• I have added necessary unit tests and integration tests

Refer to a related PR or issue link (optional)

[fuyufjh]

😇 As long as it can pass CI, LGTM

(Should merge tomorrow)

[BugenZhao]

We may move Cargo.toml to the project root as well in next PRs.

[codecov]

Codecov Report

Merging #1551 (46282dc) into main (0d04771) will decrease coverage by 0.00%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##               main    #1551      +/-   ##
============================================
- Coverage     69.70%   69.70%   -0.01%     
  Complexity     2766     2766              
============================================
  Files          1042     1042              
  Lines         91601    91601              
  Branches       1790     1790              
============================================
- Hits          63852    63850       -2     
- Misses        26858    26860       +2     
  Partials        891      891              

Flag	Coverage Δ
java	61.01% <ø> (ø)
rust	71.52% <ø> (-0.01%)	⬇️

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

Impacted Files	Coverage Δ
src/batch/src/execution/local_exchange.rs	70.93% <ø> (ø)
src/batch/src/executor/create_source.rs	0.00% <ø> (ø)
src/batch/src/executor/create_table.rs	52.54% <ø> (ø)
src/batch/src/executor/delete.rs	80.89% <ø> (ø)
src/batch/src/executor/drop_stream.rs	0.00% <ø> (ø)
src/batch/src/executor/drop_table.rs	0.00% <ø> (ø)
src/batch/src/executor/filter.rs	75.83% <ø> (ø)
src/batch/src/executor/fuse.rs	98.55% <ø> (ø)
src/batch/src/executor/generate_series.rs	66.26% <ø> (ø)
src/batch/src/executor/generic_exchange.rs	59.42% <ø> (ø)
... and 923 more

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[skyzh]

Will be merged on Sunday 12pm UTC+8