They are used to insert and remove updates from downloads when
the installation of a game changes through `RareGame.set_installed`.
They piggy-back the signals with the same names in `GlobalSignals`
When importing a game from EGL, also check
Subclass `EGLSyncListGroup` and `EGLSyncListItem` into import/export
specific classes. This way we don't have to specify the type of
operation at instatiation and improves code clarity and intention.
Signed-off-by: loathingKernel <142770+loathingKernel@users.noreply.github.com>