Add NodeBuilder for building ASTs

[jpschorr]

This is mostly a refactor of existing functionality from the parser that moves it to the ast package and makes it public.

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By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[codecov]

Codecov Report

Attention: Patch coverage is 90.32258% with 3 lines in your changes missing coverage. Please review.

Project coverage is 81.17%. Comparing base (684fff3) to head (6b27530).

Files	Patch %	Lines
partiql-ast/src/builder.rs	85.71%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #476      +/-   ##
==========================================
- Coverage   81.18%   81.17%   -0.01%     
==========================================
  Files          67       68       +1     
  Lines       18563    18570       +7     
  Branches    18563    18570       +7     
==========================================
+ Hits        15070    15074       +4     
- Misses       3051     3054       +3     
  Partials      442      442              

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[github-actions]

Conformance comparison report

	Base (684fff3)	f6b37f2	+/-
% Passing	90.35%	90.35%	0.00%
✅ Passing	5731	5731	0
❌ Failing	612	612	0
🔶 Ignored	0	0	0
Total Tests	6343	6343	0

Number passing in both: 5731

Number failing in both: 612

Number passing in Base (684fff3) but now fail: 0

Number failing in Base (684fff3) but now pass: 0