Remove Known Issues and add link to Readme (#7913)

Author: deleonio

KNOWN_ISSUES.md

@@ -96,4 +96,5 @@ Bug reports and pull requests are welcome. Please read our [contribution guide](
 - [Get Started](https://public-ui.github.io/en/docs/get-started/first-steps)
 - [Contributing](./CONTRIBUTING.md)
 - [Code of Conduct](./CODE_OF_CONDUCT.md)
+- [Known Issues](http://public-ui.github.io/en/docs/known-issues)
 - [Security](./docs/SECURITY.md)