Make issue reporter take max errors/warnings as option

The issue reporter for future parser issue output can currently not be given different values for max errors/warnings. It can also not be given an unlimited number.

This is needed when using the issue reporter to log warnings (from extra validations such as preview --migrate) when those are per all parsed manifests. The original intent was for max to be per parsed file (that is how it is currently used).

The change is simply that the values can be given as options to the issue reporter (it already supports issues).