Disable miner autostart by default
GNOME is switching to Tracker 3 by default, see Initiatives#17 (closed) for background. In the GNOME 3.38 release, there is one core app (Photos) which is not ready to switch.
We need to avoid Tracker 2.x and Tracker 3.x miners running in parallel. To solve this, we disable Tracker 2.x miners from starting automatically, and modify Photos to start the miners on demand.
Corresponding Photos branch is: gnome-photos!146 (merged)
Use of Tracker 2.x is deprecated, but the old behaviour can be restored
by passing -Dautostart=true
at configure time.