[C++] Configure row group size in dataset writting

Similar to ARROW-14426, but give the ability to set a target row group size. This might not be super important to end-users, but would help us identify what sizes are good.

Alternatively in combination with ARROW-14426, being able to set a maximum row group size might give us all the tools we need.

**Reporter**: [Jonathan Keane](https://issues.apache.org/jira/browse/ARROW-14427) / @jonkeane

_{**Note**: *This issue was originally created as [ARROW-14427](https://issues.apache.org/jira/browse/ARROW-14427). Please see the [migration documentation](https://github.com/apache/arrow/issues/14542) for further details.*}

Start by reading the related ARROW-14426 issue and the original ARROW-14427 report to understand the intended dataset-writing controls. Trace the dataset writing entry point from there and determine whether a target or maximum row group size is required; the work is done when the chosen size can be configured and its behavior is covered by the relevant tests.

Written by the indexing model from the issue text.