[FXML-5060] Add instantiation arguments to xten_nn.kernel op

[cferry-AMD]

This adds a new instantiation_args attribute to the xten_nn.kernel op, to represent instantiation arguments of templated kernels.
Optionally, the instantiation_arg_names attribute can be used to give names to the instantiation arguments. If there are names, then there must be as many names as arguments.

Instantiation arguments are integrated in the custom assembly as follows:

xten_nn.kernel "name" () instantiation_args ["N" = 42 : i32, "P" = 1 : i1]
xten_nn.kernel "name" () instantiation_args [42 : i32, 1 : i1]
xten_nn.kernel "name" () instantiation_args [2, 5]