adding some design assets including a new logo (#351)

* Create readme.MD

* update readme

* update readme

* update readme

* Update readme.MD

* update

* test

* Create test

* Create test

* Create readme.md

* masterfile logo turbo-geth

* Create readme.md

* turbo-geth logo rendered as png

* Create readme.md

* turbo-geth logo as svg

* Delete test

* colors

* colors preview + sketch library

* Delete test

* Create readme.md

* turbo-geth wallpapers + sketch file

Co-authored-by: ledgerwatch <akhounov@gmail.com>