[Rust] [DataFusion] Support date_trunc function

[asfimport]

Support date_trunc SQL function to truncate timestamps into the desired granularity similar to Postgres and other major SQL databases. For example

SELECT date_trunc(timestamp, 'day') as day, count(*) FROM orders GROUP BY day

Reporter: Pavel Tiunov

PRs and other links:

• GitHub Pull Request #9040

_{Note: This issue was originally created as ARROW-11055. Please see the migration documentation for further details.}

[asfimport]

Andrew Lamb / @alamb:
Issue resolved by pull request 9040
#9040