dns/powerdns: update 4.2.1 -> 4.3.0

Please note that 4.3.0 comes with a mandatory database schema upgrade.
See: https://doc.powerdns.com/authoritative/upgrading.html#x-to-4-3-0

• added OPTIONS LMDB backend
• removed OPTIONS MyDNS backend
• removed OPTIONS OpenDBX backend
• removed patch-fix_memleak_bindbackend
• added pidfile=/var/run/pdns/pdns_server.pid to the rc script.
• updated pkg-descr with a more descriptive blurb from their web page.

PR: 246262
Submitted by: yds@Necessitu.de
Approved by: Ralf van der Enden <tremere@cainites.net> (maintainer)
Relnotes: https://blog.powerdns.com/2020/04/07/powerdns-authoritative-4-3-0/