Temporary Runtime Components in Particle Container

[ax3l]

Summary

For diagnostics purposes in WarpX, we would like to temporarily add particle runtime components to a particle container, and deallocate them timely again to avoid large memory spikes in I/O.

This adds new functions to remove runtime components.

To Do

• doc issues in existing AddReal/IntComp: no doxygen, no mention of API contract for allocation
  • for an already allocated species, how does one add-and-allocate only the newly added runtime attributes?
• deallocation: what does a user need to do after RemoveRealComp/RemoveIntComp to deallocate the memory?

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