Remove additional config argument from Metric

[odashi]

This change removes config arguments from methods in Metric.

Overall, this argument is rarely utilized while it is not referred appropriately in many subclasses. Since we can instantiate another Metric object to use different configs, I thought that we can remove this argument without any drawbacks.

This pull request also contains some typing errors in Metric classes.

[odashi]

@neubig I think we should implement some inner singleton to hold sharable objects between the same metric instead of overriding the config.

[neubig]

Sounds good, I'd suggest we revisit that if when it becomes necessary.