Applied multi parameters to pause and unpause.
Created a new test file dedicated for pause commands.
Created a new utility function to get a slice of paused containers.
Updated documentation
Signed-off-by: André Martins <martins@noironetworks.com>
Upstream-commit: 0ce42dcc96d0f3bbfb89b23eb3c255d2ddaa9624
Component: engine
