Fix shellcheck SC2230
> which is non-standard. Use builtin 'command -v' instead.

Once applied to everything concerning OpenWrt we can disable the busybox
feature `which` and save 3.8kB.

Signed-off-by: Paul Spooren <mail@aparcar.org>

- remove Cloudflare v1 protocol support #6084 #6519
- fix goip.de update url #6448 #6519
- change Cloudflare v4 to read "Proxied" from current setting at Cloudflare Dashboard #5097 #6364 #6505
- fix replace of password inside logfile #6568
- remove myself as PKG_MAINTAINER

Signed-off-by: Christian Schoenebeck <christian.schoenebeck@gmail.com>

new ddns script for polish service FreeDNS.42.pl where you can
host your own domains for free

Signed-off-by: Michal Lipka <michal@sysadmin.care>

(commits from PR #6150 squashed together)