feat(batch): support as of now() - interval for time travel

[zwang28]

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What's changed and what's your intention?

This PR supports the syntax FOR SYSTEM TIME AS OF NOW() - INTERVAL for time travel query.

• To differentiate from temporal join's AS OF NOW/PROCTIME, time travel uses AS OF CURRENT.
• The existing Interval parser is being reused. Time travel query restricts the interval to be value + unit.

It also adds e2e tests for time travel query.

Checklist

• I have written necessary rustdoc comments
• I have added necessary unit tests and integration tests
• I have added test labels as necessary. See details.
• I have added fuzzing tests or opened an issue to track them. (Optional, recommended for new SQL features Sqlsmith: Sql feature generation #7934).
• My PR contains breaking changes. (If it deprecates some features, please create a tracking issue to remove them in the future).
• All checks passed in ./risedev check (or alias, ./risedev c)
• My PR changes performance-critical code. (Please run macro/micro-benchmarks and show the results.)

• My PR contains critical fixes that are necessary to be merged into the latest release. (Please check out the details)

Documentation

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Release note

Support time travel query to access historical data at a specific points in time.

[chenzl25]

Should we evaluate ProcessTimeWithInterval to TimestampNum at the parser? In this way, we can unify the code.

[zwang28]

I've also considered that once.
The issue is the Interval parser is not in sqlparser crate. Not sure if it's a good idea to move this Interval parser to sqlparser crate, because it'll introduce additional dependencies to sqlparser crate.

[zwang28]

It's similar to why we don't evaludate AsOf::TimestampString to AsOf::TimestampNum.

[chenzl25]

I see. ProcessTimeWithInterval((String, Option<DateTimeField>)), this enum looks a bit special because it only can represent an expression like CURRENT() - xxx but not another form. Can we use an expression instead, so that we can support a more general expression like CURRENT() + xxx - yyy

[chenzl25]

For example, this sql select now() - interval '1' Day + interval '2' hour; could be evaluated to a const value.

[zwang28]

As discussed offline, using expr as a better idea, can be done in further PR.

[chenzl25]

Rest LGTM

[chenzl25]

Let's use now() instead of current(), since now() could be used in the batch query directly and process time temporal join is no longer using now as key word.

[MrCroxx]

LGTM for the Cargo.lock.