Use load balancer configuration, not load balancer id, in job-based LB removal logic

This is required to support RCv3.
The caller `delete_server` needs to pass `lb_config`. For that `add_to_load_balancers` need to add `lb_config` to the results instead of `lb_id`. This will require lot of irritating mock testing changes. I am assuming your intention is to reuse existing `add/remove_to_lb` functions for RCv3. IMHO, it will be easier (esp for you due to mock dance) to have separate functions to add/remove from RCv3. This has many advantages: 
1. Writing your own tests which will be much better and easier than existing mock ones :). 
2. existing functions have retries based on 422 PENDING_UPDATE which is not there in rcv3. 
3. Their POST content is different. 
4. The auth part will be different and can be managed inside `launch_server` and `delete_server`
What do you think?