[chore] Improve quality of README copy and display (#735)
[chore] Improve quality of README copy and display (#735)

* Adds link to the sanity.io blog

* [comms] Improve quality of README copy and display

* Update README.md

* README.md update

* Add social and newsletter to readme.md

* Update README.md

* Update README.md

* Add links, more prose and illustrations

* Add more examples and links to them
* Make titles and link texts more descriptive
* Link to documentation with shortcuts to essential parts
* Replace screenshot with illustration
* Add shoutouts to community package maintainers

* Add missing bracket

* Misc  (#736)

- Remove Rich Date input plugin from list
- Add section about our code of conduct + link
- Link to the license file

sanity-io/sanity,sanity-io/sanity,sanity-io/sanity,sanity-io/sanity