Generate Name() method for all GoStructs

[wenovus]

This would be akin to the Node.NName() function in goyang.

This is useful when GetNode/SetNode functions are called and the schema needs to be retrieved via oc.SchemaTree["<name of GoStruct>"]

Thanks to @dan-lepage for the feedback.

[dan-lepage]

Will this ever differ from Reflect.TypeOf(struct).Name()? If not, this could also be a single ygot function, e.g. ygot.TypeName(g GoStruct).

[wenovus]

Thanks Dan, that's what I'll do.

I'd like to add this after the util packages are split. This will go to the gostruct package.