config/v2_2: copy in translator
config/v2_2: copy in translator

Copy in the 2.1.0 to 2.2.0 translator from config/translate.go, since
this package will now be expected to handle configs older than 2.2.0.

ajeddeloh/ignition,coreos/ignition,ajeddeloh/ignition,coreos/ignition,coreos/ignition,ajeddeloh/ignition