[Control Center] Tracker for version 1.1.0

This issue tracks the documentation changes for the version 1.1.0 release of Control Center.

Since there are changes that cannot be published before the release, the `[control-center-1.1.0](https://github.com/vaadin/docs/tree/control-center-1.1.0)` branch should not be merged into `latest` until the release.