Refactor IR_AccessPattern to hold an IR_AccessFunction instance instead of a lambda. Refactor IR_IV_TemporaryBuffer and add member to distinguish fragment/block-wise storage.

Add read-after-write equality test for I/O of fields with transformed layout (stream-based I/O only).

Do not read/write databuffer as whole and contiguous data block when field layout trafo was performed.

Reduce number of CI jobs

See merge request exastencils/exastencils!58

CUDA matrix reductions

See merge request exastencils/exastencils!55

# Conflicts:
#	Compiler/src/exastencils/app/ir/IR_LayerHandler.scala
#	Compiler/src/exastencils/config/Knowledge.scala
#	Compiler/src/exastencils/visualization/ir/vtk/IR_PrintVtkTriangles.scala