Move the image creation into the rpc worker

This also moves the states into the worker api so they can be shared.

Change-Id: I46124ae164f4c8ed5bc4c04a7acc11277971d1ba
Add heat stack creation in the deployer

Change-Id: Ic4ffe4d7f438c63dd10347c58d8a70e34925e04f
Add an assembly.components property

This is a convenience getter to get the components that
belong to a particular assembly

Change-Id: I0a55015e76d63f94e38ff17341014a03eaf2dcd9
Connect the completion of the image create to deploy

Change-Id: I3cf38519c258238b88af7b0f89e3adf219a14242