examples: add admin section to aws config
examples: add admin section to aws config

Without this, tectonic.service on the master will fail due to kubectl
validation errors on rbac/binding-admin.yaml.

squat/tectonic-installer,kalmog/tectonic-installer,kalmog/tectonic-installer,squat/tectonic-installer,kalmog/tectonic-installer,squat/tectonic-installer,derekhiggins/installer,squat/tectonic-installer,derekhiggins/installer