When at it, switch to generating the libzscanner bindings.

This error code has been unused in knot since 2.3, and now it got removed.

The _t isn't uint8_t* anymore but a structure with .len and .data.

libknot 2.7 stopped doing tolower inside its functions.
We're mostly OK, as packet parsing does DNSSEC canonization
(which lower-cases most things), but there are stil some places
that needed care, e.g. NSEC's next name.

To work on RRSIG TTLs, libknot >= 2.7.1 is needed.

It's not optimal; we can improve performance later.

- <dnssec/**> -> <libdnssec/**>
- <zscanner/**> -> <libzscanner/**>

nitpicks

See merge request !649

packaging - use upstream files

See merge request !648

ci: add curl to debian-stable, skip respdiff

See merge request !647

fixup! fixup! ci: do not re-run tests on master, use nightly instead

See merge request !646

Oh well, this is nightmare to debug.

fixup! ci: do not re-run tests on master, use nightly instead

See merge request !645

ci: do not re-run tests on master, use nightly instead

See merge request !644

All tests are executed before merge and we allow only fast-forward
merges so it is pointless to re-run them again on merge commit.

Code coverage and OBS will be done on auto-synchornized nightly branch.