Allow for explicit Typedef arithmetics customization

[akopich]

Currently, Typedef arithmetics relies on the operators defined for the raw types. In the absence of such, or in case of a need to overload the behaviour, the only option is to wrap the raw type into an intermediate type.

This adds customization via adding another template parameter for the arithmetics-enabling Tags.

Bug: http://b/242038642 Test: Compile, Unit