Allow the creation of a service with no metrics

Be able to create a service with no metrics (that is, no hits metric).

A newly created service contains a "hits" metric and this means we will need to handle several edge cases making our code (3scale operator) more complex and prone to error.

Can you make available an API endpoint with some optional parameter to create a service without any metrics by default?

Dev Notes

From tmaas-1
System team keep in mind that very probably UI will break for a service without hits metric. So while request is simple, consequences and thus amount of work is not. (bigger than an edge case for us).