oem: register virtualbox provider in oem
oem: register virtualbox provider in oem

This commit adds the config section for the virtualbox provider
in the oem file

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