[Feature Request] Inhibit/pause GNOME localsearch

[emansom]

Is your feature request related to a problem? Please describe.
When running under GNOME as DE, it could be busy indexing via GNOME's localsearch.

This'd negatively impact framerate consistency as it'd lead to more context switching for the scheduler and consume processor and I/O resources.

Describe the solution you'd like
For GameMode to interact with GNOME's localsearch via D-Bus and tell it to pause its indexing when GameMode is active and vice-versa.

Additional context
GNOME's localsearch can be inhibited/paused using the following command for testing. Programatically using the D-Bus API is the better route.

$ localsearch daemon --miner 'org.freedesktop.Tracker3.Miner.Files' --pause GameMode
$ localsearch daemon --miner 'org.freedesktop.Tracker3.Miner.Files' --resume 1