Merge bitcoindevkit/bdk#1082: docs: add License and Contributing sections to repo...

2d543475e2d7aa5503199699bb9bb4c0e519d0a8 docs: add License and Contributing sections to repo top-level README (Steve Myers)

Pull request description:

  ### Description

  Add explicit "License" and "Contributing" sections to the repo top-level `README.md` file to make it clear that it applies to everything in the project. Also moved license files up to repo top-level directory and did some minor cleanup of bdk/README.md License and Contribution sections to match top-level README.

ACKs for top commit:
  danielabrozzoni:
    ACK 2d543475e2d7aa5503199699bb9bb4c0e519d0a8

Tree-SHA512: 00442adf22258333d7672e8389b2380a8a81219f217bbffd525e253424a2aeeed13dd2316b3fe69d0bbeb13addbf2351697659c2abfec762e8e789fce3bb26e2

diff --cc README.md
index 5cdaa31c25d69fe01c8cbdff1507159e8d8c0c38,55eba748e9b7decd1c2b5965ada422cd4dd1d85e..d8297f733d9697ee626106876990a5c42217ef48
--- 1/README.md
--- 2/README.md
+++ b/README.md
@@@ -65,12 -65,20 +65,28 @@@ cargo update -p log --precise "0.4.18
  cargo update -p tempfile --precise "3.6.0"
  # rustls 0.21.2 has MSRV 1.60.0+
  cargo update -p rustls:0.21.6 --precise "0.21.1"
 +# tokio 1.30 has MSRV 1.63.0+
 +cargo update -p tokio:1.32.0 --precise "1.29.1"
 +# flate2 1.0.27 has MSRV 1.63.0+
 +cargo update -p flate2:1.0.27 --precise "1.0.26"
 +# reqwest 0.11.19 has MSRV 1.63.0+
 +cargo update -p reqwest --precise "0.11.18"
 +# h2 0.3.21 has MSRV 1.63.0+
 +cargo update -p h2 --precise "0.3.20"
  ```
+ 
+ ## License
+ 
+ Licensed under either of
+ 
+ * Apache License, Version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or <https://www.apache.org/licenses/LICENSE-2.0>)
+ * MIT license ([LICENSE-MIT](LICENSE-MIT) or <https://opensource.org/licenses/MIT>)
+ 
+ at your option.
+ 
+ ### Contribution
+ 
+ Unless you explicitly state otherwise, any contribution intentionally
+ submitted for inclusion in the work by you, as defined in the Apache-2.0
+ license, shall be dual licensed as above, without any additional terms or
+ conditions.