Install ns-azure: create etcd paths on disk
Install ns-azure: create etcd paths on disk

`etcd` data is now kept on a persistent disk, but a pristine disk won't
have the necessary directories.

Drive-by: install latest version (2.5.3) of sslip.io DNS server.

Fixes
<https://ci.nono.io/teams/main/pipelines/sslip.io/jobs/dns-servers/builds/736>:
```
gets the expected version number, 2.5.3 (FAILED - 1)
```

cunnie/bin,cunnie/bin,cunnie/bin,cunnie/bin,cunnie/bin,cunnie/bin,cunnie/bin