worker: add default value for network-pool
worker: add default value for network-pool

If network-pool is unset Guardian defaults to 10.80.0.0/22 which allows 1024 addresses implicitly limiting a
Guardian worker to 250 containers (4 addresses per container). This is true even if max-containers is set to
a higher value.
We set network-pool to 10.80.0.0/16 to increase the allowable addresses significantly ensuring the container
count is only limited by the explicit max-containers flag.

Signed-off-by: Muntasir Chowdhury <3af480f42ae632f8ec7bb4ce9ac5df283cd495d6@pivotal.io>

concourse/concourse,concourse/concourse,concourse/concourse,concourse/concourse,concourse/concourse