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 includes the following changes:
3326. [func] Added task list statistics: task model, worker
threads, quantum, tasks running, tasks ready.
[RT #27678]
3325. [func] Report cache statistics: memory use, number of
nodes, number of hash buckets, hit and miss counts.
[RT #27056]
3324. [test] Add better tests for ADB stats [RT #27057]
3323. [func] Report the number of buckets the resolver is using.
[RT #27020]
3322. [func] Monitor the number of active TCP and UDP dispatches.
[RT #27055]
3321. [func] Monitor the number of recursive fetches and the
number of open sockets, and report these values in
the statistics channel. [RT #27054]
3320. [func] Added support for monitoring of recursing client
count. [RT #27009]
3319. [func] Added support for monitoring of ADB entry count and
hash size. [RT #27057]
