* describe pallet evm

* add license

* write readme into lib.rs

* change some sentence

Co-authored-by: Wei Tang <accounts@that.world>

* update implementation status

Co-authored-by: Wei Tang <accounts@that.world>

* update readme according to review

* Update frame/evm/src/lib.rs

* fix line length

Co-authored-by: Wei Tang <accounts@that.world>
Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>