Ensure that the heartbeat background task is stopped before we close
the users as it accesses data within these instances.
Additionally, we also make sure that when telemetry is disabled, we stop
the background task.
Finally, `HeartbeatManager` now specifies what the desired interval is
so we can better configure the test cases.
This change ensures persistent data is stored in XDG_DATA_HOME
instead of XDG_CACHE_HOME on linux.
It adds the UserData() method on locations.Provider to return a path
suitable for storing persistent data. On linux, this returns
$XDG_DATA_HOME/protonmail (likely ~/.local/share/protonmail), and on
non-linux this returns os.UserConfigDir() because that is assumed
to be a more persistent location than os.UserCacheDir().
locations.Locations has been modified to use this new data directory;
gluon and logs are now stored here.
