Several of the string/integer/time functions are duplicated in multiple
source files for no discernable reason. Move them into fwupd-common
as private symbols instead.
The "return error and hope the client resubmits the firmware again"
pattern is clunky. There are two plugins doing this now, and about to
be one more.
This adds FwupdRequest which provides a structured way of asking the
user to perform an action, e.g. to replug the device or to press a
special key or button.
This replaces much of the UpdateMessage and UpdateImage API although
it is still used internally. Clients capable of processing the new
DeviceRequest signal should add REQUESTS to their feature flags.
Also, this allows us go back to the old meaning of _NEEDS_BOOTLOADER,
which was "needs rebooting into a bootloader mode" rather than the
slightly weird "user needs to do something and resubmit request".
