Bounded sampling

[AMLattanzi]

Summary

The get_line_data and get_slice_data routines do not currently allow for a natural way to bound the returned MultiFab. In the former case, the line length is dictated by the bottom and top of the boxarray at that level. In the latter case, the plane is dictated by the problem domain at that level.

This PR adds an optional Box argument to the get_line_data call and an optional RealBox argument to the get_slice_data call. These optional arguments bound the returned MuliFab. This feature has application in the ERF code in PR 1897 where it is of great value to sample velocities in planes/lines just upstream of a wind turbine. Since the wind turbine is small in relation to the problem domain, the bounding feature ensures the returned data is actually what the user wants.

Additional background

Checklist

The proposed changes:

• fix a bug or incorrect behavior in AMReX
• add new capabilities to AMReX
• changes answers in the test suite to more than roundoff level
• are likely to significantly affect the results of downstream AMReX users
• include documentation in the code and/or rst files, if appropriate