Use `bevy` subcrates, ie `bevy_ecs` about bevy_replicon

[Shatur]

We trying to follow Bevy guidelines and it looks like they mention default-features = false and that's what we're doing.

Looks like other popular crates do the same:

• leafwing-input-manager.
• bevy_xpbd.
• bevy_egui

I even remember that leafwing-input-manager changed to using bevy_* crates, but after some time changed it back. Don't remember the reason for the change, but I pretty sure that @alice-i-cecily had a one...

For now we require bevy_scene enabled (it enables others, like bevy_ecs and bevy_reflect), but it's because of this module. So we could make this module optional if you want so.

[mrchantey]

Ok yeah thats good to know. I saw bevy_window is included even with default-features = false and assumed that pulls in winit which blocks compilation for my target. But yeah i was mistaken, thats upstream from winit, thanks for the explanation ill see if i can do the same for my crate.