EB checkpoint files

[drangara]

Summary

The attempt here is to write the finest level embedded boundary geometry data into a checkpoint file. When reading it, ghost values in invalid regions and the cell flags still require to be set since they are not written. The coarse levels are built the usual way from the finest level. This method could potentially save time when there are several EB iterations which can make the geometry generation step expensive. An example case added to incflo here.

Additional background

Checklist

The proposed changes:

• [ ] fix a bug or incorrect behavior in AMReX
• [x] 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