Previously, the various install paths were obtained using get_option
as needed.
This patch unifies the directory selection inside the top-level meson
file as requested in https://github.com/hughsie/colord/pull/62.
This allows us to flash hardware like the Retrode and other devices using chips
like the AT90USB1287.
The test files can be re-generated using the sample code found here:
https://github.com/hughsie/fwupd-test-firmware and are designed
to be used on the AT90USBKEY2 development board.
This also moves the tests into one file as gnome-desktop-testing-runner
intentionally randomizes the order and runs them in parallel where allowed.
Since tests like get-updates have to be run after the metadata injection simply
put these into one test that calls a simple script.
