Install podio edm

In order to inherit experiment EDM from Acts EDM one has to do something like this:

```cmake
PODIO_GENERATE_DATAMODEL(myedm myedm .yaml headers sources
UPSTREAM_EDM edm4hep:${ACTS_EDM_DATA_DIR}/edm.yaml
IO_BACKEND_HANDLERS ${PODIO_IO_HANDLERS}
OUTPUT_FOLDER ${CMAKE_CURRENT_BINARY_DIR}
)
```

The problem is that [edm.yaml](https://github.com/acts-project/acts/blob/main/Plugins/Podio/edm.yml) is not being installed anywhere.

Providing something like `ACTS_EDM_DATA_DIR` or maybe directly `ACTS_PODIO_EDM_YAML` variable in cmake config would also simplify life and appreciated.