Allow the creation of a service with no mapping rules

Working on the 3scale Operator, we want to be able to create a new service, that doesn't contain any mapping rule already.

A newly created service contains some mapping rules 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 mapping rules by default?

Dev Notes

This does not apply to the first service automatically created when we create the tenant.
In API, set flag to not create this stuff?