The provisioning scripts supports prebuilt binaries. When available,
those are extracted taken into use. If they are not found,
sources are downloaded and built.
Task-number: QTQAINFRA-2066
Change-Id: Id1a59be2d1cbdb29d316ade572c3ce8f17ad3a6b
Reviewed-by: Heikki Halmet <heikki.halmet@qt.io>