Generates a partiql prelude for PLK

[RCHowell]

Relevant Issues

https://github.com/orgs/partiql/discussions/64

Description

• What? — It dumps the existing (0.14) routines (ops/functions/aggregations) to a definitions file a’la substrait extensions.
• Why? — We have to redefine all of the functions on PType now, so this is our indirection (which partiql-lang-rust may leverage)

This commit writes the current function signatures and variants to Ion files (like substrait extensions) so that PartiQL function signatures can be expressed independently of implementations. I am using these for my PR which moves functions out of SPI and into planner/eval respectively.

Open Questions

• What might be some limitations of this representation?
• Are the types sane for defining inputs/outputs?
• How might packaging/namespacing fit into this? i.e. why even have sql99::… and partiql::… namespaces?
• Is there value in these being public and consumed across PartiQL implementations, or is it just a nice-to-have for plk developers.
• Where might these live long term if shared?
• How are signatures stringified (specific/key) for representing in a plan?

License Information

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-Cross Engine

	Base (legacy)	eval	+/-
% Passing	92.59%	87.05%	-5.53%
✅ Passing	5420	5097	-323
❌ Failing	434	758	324
🔶 Ignored	0	0	0
Total Tests	5854	5855	1
Number passing in both: 4894

Number failing in both: 231

Number passing in legacy engine but fail in eval engine: 527

Number failing in legacy engine but pass in eval engine: 203
⁉️ CONFORMANCE REPORT REGRESSION DETECTED ⁉️
The complete list can be found in GitHub CI summary, either from Step Summary or in the Artifact.
203 test(s) were failing in legacy but now pass in eval. Before merging, confirm they are intended to pass.
The complete list can be found in GitHub CI summary, either from Step Summary or in the Artifact.

Conformance comparison report-Cross Commit-LEGACY

	Base (4dd0972)	3852092	+/-
% Passing	92.59%	92.59%	0.00%
✅ Passing	5420	5420	0
❌ Failing	434	434	0
🔶 Ignored	0	0	0
Total Tests	5854	5854	0
Number passing in both: 5420

Number failing in both: 434

Number passing in Base (4dd0972) but now fail: 0

Number failing in Base (4dd0972) but now pass: 0

Conformance comparison report-Cross Commit-EVAL

	Base (4dd0972)	3852092	+/-
% Passing	87.05%	87.05%	0.00%
✅ Passing	5097	5097	0
❌ Failing	758	758	0
🔶 Ignored	0	0	0
Total Tests	5855	5855	0
Number passing in both: 5097

Number failing in both: 758

Number passing in Base (4dd0972) but now fail: 1

Number failing in Base (4dd0972) but now pass: 1
⁉️ CONFORMANCE REPORT REGRESSION DETECTED ⁉️. The following test(s) were previously passing but now fail:

Click here to see

• Example 6 — Value Coercion, compileOption: LEGACY

The following test(s) were previously failing but now pass. Before merging, confirm they are intended to pass:

Click here to see

• Example 6 — Value Coercion, compileOption: LEGACY