collect gateway type and version with usage reporting

We can show the customers which router versions they are using. The information can be sent to the usage reporting service via a HTTP header `x-hive-gateway-name` and `x-hive-gateway-version`.

Some possible values for `x-hive-gateway-name`:
- `apollo-gateway`
- `apollo-router`
- `hive-gateway`
- `hive-router`
- `grafbase-router`