The current test infrastruture only exercises "ade sysroot".
This test add support to exercise "ade configure" using a mock project
implementation that lures "ade configure" as if a real project was
being configured.
This is done because the test sysroots do not have real autotools.

Apertis: https://phabricator.apertis.org/T3777



Signed-off-by: Frédéric Dalleau <frederic.dalleau@collabora.com>
Reviewed-by: Emanuele Aina <emanuele.aina@collabora.com>
Differential Revision: https://phabricator.apertis.org/D6413