chore(expr): move several expressions to expr_impl

[wangrunji0408]

I hereby agree to the terms of the RisingWave Labs, Inc. Contributor License Agreement.

What's changed and what's your intention?

Tips: click here to review code, ignoring file moves.

This PR moves the following expressions from expr crate to expr_impl crate:

• in
• coalesce
• field
• vnode
• array_transform

and migrates their constructors to #[build_function], as well as their unit tests.

The syntax of struct types in DataChunk::from_pretty is changed to match postgres literals.

- {i,f}
- {1,1.0}
+ <i,f>
+ (1,1.0)

The risingwave_udf crate is moved to the expr folder.

Checklist

• I have written necessary rustdoc comments
• I have added necessary unit tests and integration tests
• I have added test labels as necessary. See details.
• I have added fuzzing tests or opened an issue to track them. (Optional, recommended for new SQL features Sqlsmith: Sql feature generation #7934).
• My PR contains breaking changes. (If it deprecates some features, please create a tracking issue to remove them in the future).
• All checks passed in ./risedev check (or alias, ./risedev c)
• My PR changes performance-critical code. (Please run macro/micro-benchmarks and show the results.)

• My PR contains critical fixes that are necessary to be merged into the latest release. (Please check out the details)

Documentation

• My PR needs documentation updates. (Please use the Release note section below to summarize the impact on users)

[codecov]

Codecov Report

Attention: 105 lines in your changes are missing coverage. Please review.

Comparison is base (98b0ebd) 68.07% compared to head (5da78a9) 68.10%.
Report is 4 commits behind head on main.

Files	Patch %	Lines
src/storage/src/hummock/sstable_store.rs	67.42%	43 Missing ⚠️
...ge/src/hummock/sstable/forward_sstable_iterator.rs	83.05%	10 Missing ⚠️
src/storage/src/hummock/block_stream.rs	91.66%	8 Missing ⚠️
src/expr/impl/src/scalar/field.rs	85.10%	7 Missing ⚠️
src/storage/src/hummock/utils.rs	81.25%	6 Missing ⚠️
src/expr/impl/src/scalar/coalesce.rs	91.80%	5 Missing ⚠️
src/storage/src/store.rs	73.68%	5 Missing ⚠️
src/expr/impl/src/scalar/vnode.rs	91.11%	4 Missing ⚠️
src/expr/core/src/expr/mod.rs	0.00%	3 Missing ⚠️
src/expr/core/src/expr/wrapper/checked.rs	0.00%	3 Missing ⚠️
... and 6 more

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #13923      +/-   ##
==========================================
+ Coverage   68.07%   68.10%   +0.02%     
==========================================
  Files        1532     1533       +1     
  Lines      264568   264434     -134     
==========================================
- Hits       180114   180094      -20     
+ Misses      84454    84340     -114     

Flag	Coverage Δ
rust	68.10% <85.29%> (+0.02%)	⬆️

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

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.