feat(cubesql): Add filter flattening rule

[mcheshkov]

Check List

• Tests have been run in packages where changes made if available
• Linter has been run for changed code
• Tests for the changes have been added if not covered yet
• Docs have been added / updated if required

Description of Changes Made (if issue reference is not provided)

Allow to flatten filter node into internal WrappedSelect. This should allow to execute plans like Aggregate(Filter(Join(...))) as a single grouped wrapper.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 83.16%. Comparing base (50bdbe7) to head (7237e27).
Report is 3 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #9148      +/-   ##
==========================================
+ Coverage   83.11%   83.16%   +0.05%     
==========================================
  Files         226      226              
  Lines       79797    80047     +250     
==========================================
+ Hits        66321    66570     +249     
- Misses      13476    13477       +1     

Flag	Coverage Δ
cubesql	83.16% <100.00%> (+0.05%)	⬆️

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