Halo exchange uses arrays

[FlorianDeconinck]

Purpose

Our Halo Exchange use a pattern of memory specification at init and then at runtime passing the actual memory to be exchanged. The type of the parameters is Quantity, but truly it doesn't need such a high level concept and simple arrays would do. Moving to simple arrays would allow for DaCe orchestration to use the same code pattern.

Code changes:

• Move runtime of halo exchange to work on arrays
• Remove all reference to state & tracers at init time now that they are superflous

Checklist

Before submitting this PR, please make sure:

• You have followed the coding standards guidelines established at Code Review Checklist.
• Docstrings and type hints are added to new and updated routines, as appropriate
• All relevant documentation has been updated or added (e.g. README, CONTRIBUTING docs)
• For each public change and fix in pace-util, HISTORY has been updated
• Unit tests are added or updated for non-stencil code changes