oem: add coreos-metadata config to ec2
oem: add coreos-metadata config to ec2

This enables the fetching of SSH keys for the core user on EC2.

ajeddeloh/ignition,ajeddeloh/ignition,AlexNPavel/ignition,dgonyeo/ignition,coreos/ignition,coreos/ignition,dgonyeo/ignition,higebu/ignition,coreos/ignition,higebu/ignition,higebu/ignition,dgonyeo/ignition,AlexNPavel/ignition,AlexNPavel/ignition,ajeddeloh/ignition