[flang][cuda] Lower attribute for local variable (#81076)

This is a first simple patch to introduce a new FIR attribute to carry
the CUDA variable attribute information to hlfir.declare and fir.declare
operations. It currently lowers this information for local variables.

The texture attribute is omitted since it is rejected by semantic and
will not make its way to MLIR.

This new attribute is added as optional attribute to the hlfir.declare
and fir.declare operations.