A huge list of initial work for service steps
* Adds service_step verb
* Adds service_step db/object/API field on the node object for the
status.
* Increments the API version to 1.87 for both changes.
* Increments the RPC API version to 1.57.
* Adds initial testing to facilitate ensurance that supplied steps
are passed through and executed upon.
Does not:
* Have tests for starting the agent ramdisk, although this is
relatively boiler plate.
* Have a collection of pre-decorated steps available for immediate
consumption.
Change-Id: I5b9dd928f24dff7877a4ab8dc7b743058cace994
2366a4b86e