Draft: Changes for compatibility with pystencils 2.0

Introduce a significant number of patches for compatibility with the upcoming pystencils 2.0.

Status:

• Fix field duplication in create_lb_update_rule: Remove the workaround once field duplication is fixed in pystencils
• Data types in boundary handling: LatticeBoltzmannBoundaryHandling does not allow to specify a data type and always uses float64. This leads to type errors when combined with LB fields with float32 dtype.
• Mixed precision: Need to explicitly insert casts at field reads/writes when computing and storing PDFs in different float formats

src/lbmpy/boundaries/boundaryhandling.py

@@ -4,7 +4,6 @@ import numpy as np
 from pystencils import Assignment, CreateKernelConfig, create_kernel, Field, Target, FieldType
 from pystencils.boundaries import BoundaryHandling
 from pystencils.boundaries.createindexlist import numpy_data_type_for_boundary_object
-from pystencils.field import FieldType
 from pystencils.simp import add_subexpressions_for_field_reads
 from pystencils.stencil import inverse_direction