Align README with 1.8 and prepare CHANGELOG with 1.8.1 (#6833)

* Update README.md for 1.8.0

* Update CHANGELOG.md for 1.8.1

* Clarify note on trezor wallets

* Update CHANGELOG.md for 1.8.1

* Update CHANGELOG.md for 1.8.1

* Update CHANGELOG.md for 1.8.1

* Fix Typos.