MULE-8028 - adding support for mule client in http connector

I don't have a magic number, I was just asking because in this context 1000 means that 1000 different URLs that were hit in the application in the last 10 minutes. Seems too much for me.
Given that this class is now being used in many different context it could be an improvement to add system properties to be able to change this default values. (in a different JIRA off course)