refactor!: proof_of_sql_parser::intermediate_ast::PoSQLTimezone with sqlparser::ast::TimezoneInfo in the proof-of-sql crate

[varshith257]

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Rationale for this change

This PR addresses the need to replace the proof_of_sql_parser::PoSQLTime with the sqlparser::ast::TimezoneInfo in the proof-of-sql crate as part of a larger transition toward integrating the sqlparser .

This change is a subtask of issue #235, with the main goal of streamlining the repository by switching to the sqlparser crate and gradually replacing intermediary constructs like proof_of_sql_parser::intermediate_ast with sqlparser::ast.

What changes are included in this PR?

• All instances of proof_of_sql_parser::PoSQLTimeZone have been replaced with sqlparser::ast::TimezoneInfo
• Every usage of PoSQLTimeZone has been updated to maintain the original functionality, ensuring no changes to the logic or behavior.
• The breaking change here is that TimeZoneInfo doesn't support offset and a trait has been added for it

Are these changes tested?

Yes

Part of #235
Part of #351

Note for Reviewers

• PosqlTimeUnit has been kept intact due to sqlparser::ast not having related structures or enums to do so.
• PosqlTimeStamp will be refactored in Literal -> ast::Expr PR as PosqlTimeStamp has been integrated with Literal::TimeStampTZ, which makes refactor redundant in this PR. I have included a util function for the refactor of TimeStamp

[Dustin-Ray]

Wait sorry what is the point of this PR? Is it that sqlparser has a requirement for timestamps without timezone information? Also, Im not sure if this branch should merge without being deployed and smoke tested in the ProofsService crate first as this may end up causing breaking changes, but Im not really sure without trying it.

Lastly, Im not at all against removing the TimeUnit if it isnt supported by sqlparser. Removing the TimeUnit and just defaulting into nanoseconds would vastly simplify the codebase in many places, but maybe the trait introduced here mitigates that issue.

[varshith257]

@iajoiner @Dustin-Ray Thanks for reviewing!

I don't believe removing PoSQLTimeUnit and defaulting to nanoseconds would be the best approach. PoSQLTimeUnit provides flexibility for handling various time precision units such as seconds, milliseconds, microseconds and nanoseconds. IMO each time unit can have its practical use case and removing that flexibility may reduce the granularity and precision options available now in PoSQL

[iajoiner]

@Dustin-Ray @varshith257 Yeah I think it is probably easier to just default to nanoseconds here.

[iajoiner]

Why not remove this file entirely?

[varshith257]

Reverted nanoseconds defaulting change as per discussions