Add experimental draft support for GPML-style graph query parsing

[jpschorr]

This adds addtional features to the draft parser/AST support for a subset of GPML as outlined by Graph Pattern Matching in GQL and SQL/PGQ. The use within the grammar is based on the assumption of a new graph data type being added to the specification of data types within PartiQL, and should be considered experimental until the semantics of the graph data type are specified.

Added by this PR:

• basic and abbreviated node and edge patterns (section 4.1 of the GPML paper)
• concatenated path patterns (section 4.2 of the GPML paper)
• path variables (section 4.2 of the GPML paper)
• graph patterns (i.e., comma separated path patterns) (section 4.3 of the GPML paper)
• AST support for path quantifiers (section 4.4 of the GPML paper)
• parenthesized patterns (section 4.4 of the GPML paper)
• parsing support for path quantifiers (section 4.4 of the GPML paper)
• restrictors and selector (section 5.1 of the GPML paper)
• parsing support for pre-filters and post-filters (section 5.2 of the GPML paper)
• AST support for pre-filters (section 5.2 of the GPML paper)

GPML features not yet implemented:

• group variables (section 4.4 of the GPML paper)
• path pattern union and multiset (section 4.5 of the GPML paper)
• conditional variables (section 4.6 of the GPML paper)
• graphical predicates (section 4.7 of the GPML paper)
• aggregates of unbounded variables (section 5.3 of the GPML paper)

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Similar functionality and test cases as introduced by:

• Add experimental draft support for GPML-style graph query partiql-lang-kotlin#652
• Extend experimental draft support for GPML-style graph query partiql-lang-kotlin#658
• Switched from MATCH-as-FROM-source to MATCH-as-expression partiql-lang-kotlin#797

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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.

[github-actions]

Conformance comparison report

	main (17cbcb5)	7803e5d	+/-
% Passing	78.00%	78.00%	0.00%
✅ Passing	344	344	0
❌ Failing	0	0	0
🔶 Ignored	97	97	0
Total Tests	441	441	0

Number passing in both: 344

Number failing in both: 0

Number passing in main but now fail: 0

Number failing in main but now pass: 0

[codecov]

Codecov Report

Base: 87.32% // Head: 87.53% // Increases project coverage by +0.21% 🎉

Coverage data is based on head (b8180c5) compared to base (17cbcb5).
Patch coverage: 91.47% of modified lines in pull request are covered.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #148      +/-   ##
==========================================
+ Coverage   87.32%   87.53%   +0.21%     
==========================================
  Files          23       23              
  Lines        2383     2512     +129     
==========================================
+ Hits         2081     2199     +118     
- Misses        302      313      +11     

Impacted Files	Coverage Δ
partiql-parser/src/lexer.rs	97.09% <0.00%> (-0.19%)	⬇️
partiql-ast/src/ast.rs	50.89% <78.26%> (+3.64%)	⬆️
partiql-parser/src/parse/mod.rs	94.88% <100.00%> (+1.13%)	⬆️

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