MicroCloud should validate API/Schema versions before clustering

Attempting to set up MicroCloud with services (LXD, MicroCeph, MicroOVN) that have mismatched API/Schema versions, the setup will happily move along and then fail during those services' own version validation when forming the cluster with the error or one like it:

```
Error: Peer "n2" failed to join the cluster: Failed to update cluster status of services: Failed to join "LXD" cluster: Failed to configure cluster: Failed request to add member: The joining server version doesn't match (expected 5.18 with API count 360)
```

MicroCloud should instead incorporate the API versions of each service into the `mdns` response so that the system doing the lookup (calling `microcloud init`) can properly ignore them with a syslog message reporting that the node was skipped due to a version mismatch.