WIP: Rackconnect v3 Load Balancer Pool support

This provides API support for RackConnect V3 load balancers.  First ask of #104 

UPDATE 11/14:  Magic session reset bug is fixed by #110.  Still missing:

- [ ] Test coverage for bulk add to/delete from MULTIPLE load balancers instead of just one
- [ ] `seconds_to_timestamp` tests
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