Move node check to spawn from call
create/0,1,2: spawn for any executable

Move the container creation out of spawn so that any executable can be
run as init. spawn waits for the distributed erlang node to boot before
returning.
Generate the container name using a template
callopt/2: call with options

Add a call with options for use in a pipeline. For example, the IP
address of the container can be hardcoded to avoid DHCP requests:

    {:lists, :reverse, ['hello']}
      |> Ampule.callopt([ipaddr: "192.168.123.99"])