Add draining_time to LBConfig for now
Add last updated time to LBNode
Add a step that sets a metadata item on a server
Change server status to NamedConstants rather than strings, and add DELETING as a state
Revert "Add draining_time to LBConfig for now"

This reverts commit 60abdbe269bf9b98d52dc117b032526f0cf1a467.
Revert "Add last updated time to LBNode"

This reverts commit 8fb1cbf313cbbbe510b84fb4ddb176b8eeab001f.
Merge branch 'master' into converge-draining
Add remove from lb helper function that handles draining and draining timeouts
Remove 'draining timeout' attribute per load balancer config
Oops, now should just be a float
Add function to drain or delete a server
Add replace delete server logic with _drain_and_delete_server, and change those tests to test the converge function operating on a scaledown instead
Small refactoring
Generalize optimization function
Add optimization test
Add test for removal
Some work on steps
Tasty delicious docstrings
Change ACTIVE, BUILD, and ERROR to NamedConstants, and do some test cleanup because load balancers with cheese is a list
Move draining timeout from a per-node load balancer config attribute to an attribute in desired state