- Add LICENSE-APACHE (Apache License 2.0 full text)
- Add LICENSE-GPL3 (GNU GPL 3.0 full text)
- Add NOTICE file with full attribution to original Polkadot SDK,
Parity Technologies (UK) Ltd., and Web3 Foundation, documenting
all significant changes made as required by Apache-2.0 Section 4(b)
- Update README License section to accurately reflect dual licensing
and link to NOTICE file
