feat(postgres): implement support for asof_join API via a lateral join

[zblz]

Description of changes

Implement support for asof_join API in postgres compiler. The implementations works around the lack of ASOF key in Postgres by implementing it as a lateral subquery join. This implementation is inspired by some posts on this thread of the pg-hackers mailing list.

[github-actions]

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The commitlint output is:

npm warn exec The following package was not found and will be installed: [email protected]
⧗   input: feat(postgres): Implement support for `asof_join` API via a lateral join

## Description of changes

Implement support for `asof_join` API in postgres compiler. The implementations works around the lack of ASOF key in Postgres by implementing it as a lateral subquery join. This implementation is inspired by some posts on [this thread](https://www.postgresql.org/message-id/flat/bc494762-26bd-b100-e1f9-a97901ddad57%40postgrespro.ru) of the `pg-hackers` mailing list.
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[cpcloud]

Awesome, great work, thank you!