[PoC] Add column metadata to Query object

[suddendust]

Description

This is a PoC that demos how we can pass column metadata like their canonical types from entity-service to document-store. This information can be used by document-store to support features like unnest/access nested attributes in flat PG collections.

[codecov]

Codecov Report

❌ Patch coverage is 21.42857% with 22 lines in your changes missing coverage. Please review.
✅ Project coverage is 79.04%. Comparing base (3cc020b) to head (77a51c1).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
...trace/core/documentstore/query/ColumnMetadata.java	29.41%	10 Missing and 2 partials ⚠️
...org/hypertrace/core/documentstore/query/Query.java	9.09%	9 Missing and 1 partial ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main     #238      +/-   ##
============================================
- Coverage     79.35%   79.04%   -0.31%     
- Complexity     1078     1083       +5     
============================================
  Files           208      209       +1     
  Lines          5276     5303      +27     
  Branches        453      458       +5     
============================================
+ Hits           4187     4192       +5     
- Misses          770      789      +19     
- Partials        319      322       +3     

Flag	Coverage Δ
integration	79.04% <21.42%> (-0.31%)	⬇️
unit	56.68% <21.42%> (-0.20%)	⬇️

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