[mlir][ods] Adding attribute setters generation

In some dialects, attributes may have default values that may be
determined only after shape inference. For example, attributes that
are dependent on the rank of the input cannot be assigned a default
value until the rank of the tensor is inferred.

While we can set attributes without explicit setters, referring to
the attributes via accessors instead of having to use the string
interface is better for compile time verification.

The proposed patch add one method per operation attribute that let us
set its value. The code is a very small modification of the existing
getter methods.

Differential Revision: https://reviews.llvm.org/D74143