dns/ddclient: Added multihost support for cloudflare service

[cektom]

This enables updates for multiple hosts for cloudflare service.
Tested on OPNsense 24.7.11_2

[AdSchellevis]

I'll leave this open for a bit as some other account types on our end are implemented similarly, but in general there are side affects of iterating hosts like this.

When X hosts are being updated and only one is successfully changed, the service assumes all went file, which isn't the case. By just coping the entries, the recorded state matches reality.

Originally the hostnames implementation was intended for dyndns, which supports multiple names in the same transaction (https://sourceforge.net/p/ddclient/wiki/protocols/#dyndns2)

[cektom]

Alright. I checked the API documentation, but unfortunately it is currently not possible to update multiple hostnames at once.