GPU-compatible neighborhood search

[efaulhaber]

Based on #562 and trixi-framework/PointNeighbors.jl#45.

With this PR, we can use the GridNeighborhoodSearch with the FullGridCellList on GPUs.

[codecov]

Codecov Report

Attention: Patch coverage is 46.66667% with 8 lines in your changes missing coverage. Please review.

Project coverage is 69.65%. Comparing base (b82162f) to head (1784c41).

Files	Patch %	Lines
src/general/semidiscretization.jl	42.85%	8 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #563      +/-   ##
==========================================
- Coverage   69.70%   69.65%   -0.06%     
==========================================
  Files          75       75              
  Lines        4555     4557       +2     
==========================================
- Hits         3175     3174       -1     
- Misses       1380     1383       +3     

Flag	Coverage Δ
unit	69.65% <46.66%> (-0.06%)	⬇️

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