Make SubActions a struct

So we can inject some its collaborators separately from using it

Signed-off-by: Alex Suraci <asuraci@pivotallabs.com>
fix execution chain factory test package location

Signed-off-by: Alex Suraci <asuraci@pivotallabs.com>
pluck container handle and actions off RunOnce

Signed-off-by: Alex Suraci <asuraci@pivotallabs.com>
rename ExecutionChainFactory to RunOnceTransformer

Signed-off-by: Alex Suraci <asuraci@pivotallabs.com>