FirmwareOfferMixin.get_firmware_offer() -> FirmwareOfferDict
{current_version, latest_version, newer, download_url?}: what runs and
the newest firmware the vendor offers, from its download catalogue or
the device's own update check. Comparing vendor version strings stays
with the driver, so it says whether the offer is newer; whether that is a
warning is the application's call (NetOrk/netork#1111). Declared only.
christianmanivong