Centralize license and MSRV boilerplate into the repo readme.

embassy-net-tuntap/README.md

@@ -5,13 +5,3 @@
 ## Interoperability
 
 This crate can run on any executor.
-
-## License
-
-This work is licensed under either of
-
-- Apache License, Version 2.0 ([LICENSE-APACHE](LICENSE-APACHE) or
-  http://www.apache.org/licenses/LICENSE-2.0)
-- MIT license ([LICENSE-MIT](LICENSE-MIT) or http://opensource.org/licenses/MIT)
-
-at your option.