(WinitPlugin) Allow control of game tick

[xiaopengli89]

Objective

Related to #1343, this PR allow dynamic control of game tick, and benefit power savings for GUI applications.

Solution

To disable the default poll game tick, insert WinitTick::new(false) resource into the world, animation systems can call poll_tick with WinitTick resource to poll game tick for the next frame.

The default default_poll_tick parameter value of WinitTick is true to prevent break changes.

Todo

• When Asset is loaded asynchronously, we should send a tick event to EventLoop.

[alice-i-cecile]

@aevyrie is this still needed?

[aevyrie]

@aevyrie is this still needed?

With #3974 merged, I don't think so. This does have a few other features, but it would need to be rewritten anyway. I'd suggest we close this, and we can add any missing functionality in small PRs as needed.