FastCS Eiger support for X-ray Centring

Following https://github.com/DiamondLightSource/dodal/pull/1187 we have a basic example of how to use the `ophyd-async` Eiger. We should add the ability to use this in Hyperion.

We will need some time for soak testing, particularly as the `ophyd-async` Eiger uses a different IOC, which is running on K8s. So we will need to be able to control which Eiger we use from a GDA property (e.g. a parameter in the model sent to Hyperion)

## Acceptance Criteria
- There is a parameter I can send to Hyperion which makes us use the `ophyd-async` Eiger