Allow user to define custom retriable message

Currently when a user identifies an error/exception that has to be made retriable it needs to wait for the next release to have error handler updated.

This is proposal for a new internal config option that when present take an error marked as non-retriable, run all stacktrace messages through a regular expression defined in the option and if matches then it will handle the error as retriable.

This woula act as a workaround till the next release with updated error handler.