support regex in topic.namespace.map ( kafka source connector )

Currently, `topic.namespace.map` supports wildcard ( * ). It will be helpful if it also support regex as well. Or, since it can be breaking change, it would be nice if a new mapping is introduced that supports regex format. The workaround can be using custom mapper. However, if the there is an builtin version, then the wheel can invented once and used by many ppl.