Add director client class for use in automated deployer.

[#52819141]

Signed-off-by: Matthew Boedicker <mboedicker@pivotallabs.com>
Add has_stemcell? method to director client.

Signed-off-by: Tony Hansmann <thansmann@pivotallabs.com>
Use DirectorClient instead of Cli::Director

Fixed newing up the wrong object.
Extracted 2 smaller methods out of the big deploy method, but
leaving it as the only public interface.
Strict ordering in tests.

Signed-off-by: Jesse Zhang <jz@pivotallabs.com>
Better testing of stemcell uploading in AutomatedDeployer

Signed-off-by: Jesse Zhang <jz@pivotallabs.com>