At the moment we just blindly assume the capabilities of the front-end client
when installing firmware. We can somewhat work around by requiring a new enough
fwupd daemon version, but the client software may be older or just incomplete.
This would allow, for instance, the firmware to specify that it requries the
client to be able to show a detach image. This would not be set by a command
line tool using FwupdClient, but would be set by a GUI client that is capable
of downloading a URL and showing a PNG image.
Clients that do not register features are assumed to be dumb.
