feat: implement AVG aggregation of the datafusion planner

[ChunxuTang]

This PR:

• adds the support of AVG (AVERAGE) aggregation function of the datafusion planner
• adds the validation of properties of SUM/AVG/MIN/MAX (e.g. SUM(p.name)) in the semantic analysis, so we don't need to rehandle the illegal cases in the datafusion planner

[codecov-commenter]

Codecov Report

❌ Patch coverage is 90.00000% with 13 lines in your changes missing coverage. Please review.
⚠️ Please upload report for BASE (main@7625f3d). Learn more about missing BASE report.

Files with missing lines	Patch %	Lines
rust/lance-graph/src/semantic.rs	89.90%	11 Missing ⚠️
...t/lance-graph/src/datafusion_planner/expression.rs	90.47%	2 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main      #42   +/-   ##
=======================================
  Coverage        ?   81.93%           
=======================================
  Files           ?       23           
  Lines           ?     8532           
  Branches        ?        0           
=======================================
  Hits            ?     6991           
  Misses          ?     1541           
  Partials        ?        0           

Flag	Coverage Δ
rust-unittests	81.93% <90.00%> (?)

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