container: add the possibility to specify the node on CreateContainer

This features enable the following flow:

	1. Try to create the container and receives a 404 (i.e. no such
	   image)
	2. Pull the image (we will need to be able to specify the node
	   here too)
	3. Create the container in the same node of the first try
container: add test for unknown node in create container with node param
container: integrate node specification with storage
image: support for specifying the list of nodes in PullImage

See 8b44031cb6f2d2c42bfa0dd8f13a7bc56d00105e for more details.