[C++] Temporal floor/ceil/round should have settable origin unit

Temporal rounding kernels (will) allow setting of rounding origin to a greater unit. This could be made more flexible by introducing a `greater_unit` parameter which would let user select the unit serving as origin. See [this discussion](https://github.com/apache/arrow/pull/12657#issuecomment-1119580484) for more context.

**Reporter**: [Rok Mihevc](https://issues.apache.org/jira/browse/ARROW-16535) / @rok
**Watchers**: [Rok Mihevc](https://issues.apache.org/jira/browse/ARROW-16535) / @rok

_{**Note**: *This issue was originally created as [ARROW-16535](https://issues.apache.org/jira/browse/ARROW-16535). Please see the [migration documentation](https://github.com/apache/arrow/issues/14542) for further details.*}

Start by locating the C++ temporal rounding kernels referenced in the issue and read the linked discussion for the intended origin-unit behavior. The change is complete when floor, ceil, and round accept a greater_unit parameter that selects the unit serving as the rounding origin.

Written by the indexing model from the issue text.