Let the project page support GitHub's new ability to display open source licenses (bevyengine#4966)

Change _LICENSE-APACHE_ and _LICENSE-MIT_ file location
Delete _LICENSE_
You can make the license in about on bevy's GitHub page display as **Apache-2.0, MIT licenses found** instead of **View license**

Author: C-BJ

LICENSE

@@ -100,8 +100,8 @@ Additionally, we would like to thank the [Amethyst](https://github.com/amethyst/
 
 Bevy is free and open source! All code in this repository is dual-licensed under either:
 
-* MIT License ([LICENSE-MIT](docs/LICENSE-MIT) or [http://opensource.org/licenses/MIT](http://opensource.org/licenses/MIT))
-* Apache License, Version 2.0 ([LICENSE-APACHE](docs/LICENSE-APACHE) or [http://www.apache.org/licenses/LICENSE-2.0](http://www.apache.org/licenses/LICENSE-2.0))
+* MIT License ([LICENSE-MIT](LICENSE-MIT) or [http://opensource.org/licenses/MIT](http://opensource.org/licenses/MIT))
+* Apache License, Version 2.0 ([LICENSE-APACHE](LICENSE-APACHE) or [http://www.apache.org/licenses/LICENSE-2.0](http://www.apache.org/licenses/LICENSE-2.0))
 
 at your option. This means you can select the license you prefer! This dual-licensing approach is the de-facto standard in the Rust ecosystem and there are [very good reasons](https://github.com/bevyengine/bevy/issues/2373) to include both.