Added DNS seed

Obfuscode.Net is now hosting a DNS-seed that is periodically updated by myself.

It includes following nodes by the time of writing:
```text
seed.qb.obfuscode.net.  48      IN      A       46.246.25.91
seed.qb.obfuscode.net.  48      IN      A       23.226.130.190
seed.qb.obfuscode.net.  48      IN      A       72.9.151.248
seed.qb.obfuscode.net.  48      IN      A       62.210.162.235
seed.qb.obfuscode.net.  48      IN      A       162.243.248.229
```

The DNS-TTL is set to 1 hour so updates are pushed quickly without producing too much redundant loads.