Alarm Control Panel - Add "Ready/Fault" attribute

**Describe the problem you have/What new integration you would like**

On the Alarm Control Panel Core, add an attribute for "Ready" or "Fault" based on the status of the binary sensors.
**Please describe your use case for this integration and alternatives you've tried:**

Add an attribute that can be checked showing the status of the binary sensors. This can be used to show on a status LED or on a display, if the alarm is ready to be armed or not.
If all the binary sensors are closed, then the attribute would show "Ready", if any of the binary sensors are opened, then the attribute would show "Fault".
**Additional context**

Right now there is no way of knowing if the alarm is ready to be armed or if there are any zones that are opened.

Start at the Alarm Control Panel Core and inspect how its binary sensor statuses are represented. Done means the panel exposes a Ready attribute when all binary sensors are closed and a Fault attribute when any binary sensor is open, suitable for display or status-LED checks.

Written by the indexing model from the issue text.