[C++] Temporal floor/ceil/round should accept week_starts_monday when rounding to multiple of week

[asfimport]

See ARROW-14821 and the related PR.

Reporter: Rok Mihevc / @rok
Assignee: Rok Mihevc / @rok
Watchers: Rok Mihevc / @rok

Related issues:

• [R] Implement bindings for lubridate's floor_date, ceiling_date, and round_date (blocks)

PRs and other links:

• GitHub Pull Request #12515

_{Note: This issue was originally created as ARROW-15680. Please see the migration documentation for further details.}

[asfimport]

Dragoș Moldovan-Grünfeld / @dragosmg:
@pitrou  this is the issue I mentioned on the Labs call

[asfimport]

David Li / @lidavidm:
Issue resolved by pull request 12515
#12515