This commit converts the license handling to adhere to the REUSE
specification. It specifically:
1. Adds used licnses to LICENSES/ directory
2. Add "isc" template for adding the copyright boilerplate
3. Changes all source files to include copyright and SPDX license
header, this includes all the C sources, documentation, zone files,
configuration files. There are notes in the doc/dev/copyrights file
on how to add correct headers to the new files.
4. Handle the rest that can't be modified via .reuse/dep5 file. The
binary (or otherwise unmodifiable) files could have license places
next to them in <foo>.license file, but this would lead to cluttered
repository and most of the files handled in the .reuse/dep5 file are
system test files.
This test asserts that option "deny-answer-aliases" works correctly
when forwarding requests.
As a matter of example, the behavior expected for a forwarder BIND
instance, having an option such as deny-answer-aliases { "domain"; }
is that when forwarding a request for *.anything-but-domain, it is
expected that it will return SERVFAIL if any answer received has a CNAME
for "*.domain".
(cherry picked from commit 9bdb960a16a69997b08746e698b6b02c8dc6c795)
