This allows us to 'nest' firmware formats, and removes a ton of duplication.
The aim here is to deprecate FuFirmwareImage -- it's almost always acting
as a 'child' FuFirmware instance, and even copies most of the vfuncs to allow
custom types. If I'm struggling to work out what should be a FuFirmware and
what should be a FuFirmwareImage then a plugin author has no hope.
For simple payloads we were adding bytes into an image and then the image into
a firmware. This gets really messy when most plugins are treating the FuFirmware
*as* the binary firmware file.
The GBytes saved in the FuFirmware would be considered the payload with the
aim of not using FuFirmwareImage in the single-image case.
The FWUPD_INSTALL_FLAG_FORCE flag has really unclear semantics, and ignoring a
file CRC, checksum or model ID should only be done when using fwupdtool actually
debugging a plugin or firmware parser.
Use the existing --force flag when we want a "gentle nudge" like reuploading
previously processed reports.
