Merge branch 'dnssec_keytag_conflicts' into 'master'

Knot.files

src/Makefile.am

src/contrib/dynarray.h

src/knot/dnssec/zone-keys.c

src/knot/dnssec/zone-keys.h

src/knot/dnssec/zone-sign.c

...ta/keys/keys/301d3fc5392e83ea02312dc5bdc1a9f0b7937ddf.pem

...ta/keys/keys/6abddc73bcb46c4e6078cf764290ac315fff03f0.pem

...ta/keys/keys/712d0d0d57fa0aa006b5e20cd84e23941e5f3ab2.pem

...ta/keys/keys/7a3500c7feac3fd99f09a208a83b97f7455fa3e0.pem

...ts/dnssec/keytag_conflict/data/keys/keystore_default.json

...ts/dnssec/keytag_conflict/data/keys/zone_example.com.json

tests-extra/tests/dnssec/keytag_conflict/test.py

tests-extra/tools/dnstest/server.py