ddns-scripts: Add more services and minor changes

ddns-scripts: Add more services and minor changes

- add support of knsupdate (update_nsupdate.sh
- url update easydns.com
- add some service answers
- alphabetic reorder services files for easier reading
- rename services/provider (Makefile postinst handle /etc/config/ddns)
 -- freedns.afraid.org -> afraid.org
 -- free.editdns.net -> editdns.net
 -- domains.google.com -> google.com
 -- spdns.de -> spdyn.de
 -- strato.de -> strato.com
- new provider (looking in deep into https://sourceforge.net/projects/inadyn-mt project)
 -- dyn.com (= dyndns.org)
 -- ddnss.de
 -- dhis.org
 -- dnspark.com (IPv4 only)
 -- dynsip.org (IPv4 only)
 -- dynv6.com
 -- joker.com (IPv4 only)
 -- loopia.com (= loopia.se)
 -- sitelutions.com (IPv4 only)
 -- system-ns.com (IPv4 only)
- new provider (looking in deep into /etc.defaults/ddns_provider.conf file for Synology DiskStation published at https://gist.github.com/ntrepid8/6653274)
 -- able.or.kr (IPv4 only)
 -- ddo.jp (IPv4 only)
 -- dnsmadeeasy.com (IPv4 only)
 -- oray.com (IPv4 only)
- new provider (looking in deep into https://github.com/ipfire/ddns project)
 -- all-inkl.com
 -- desec.io
 -- domopoli.de (IPv4 only)
 -- opendns.com (IPv4 only)
 -- udmedia.de
 -- xlhost.de (IPv4 only)
- new provider (looking in deep into https://github.com/yaddns/yaddns project )
 -- dyndns.it (IPv4 only)

Signed-off-by: Christian Schoenebeck <redacted>