Enable count > 1 for AWS ELB by optionally generating random names

Name was required for AWS ELB resources, and AWS requires a unique name for each ELB. This made it so that a `count` greater than 1 would cause repeated names, which blocked the creation of all but the first ELB.

With this commit, if the name is left blank, a random name will be provided so that `count` greater than 1 can be used for ELBs.