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.
Address the following warnings reported by PyLint 2.10.2:
************* Module tests-checkds
bin/tests/system/checkds/tests-checkds.py:70:9: W1514: Using open without explicitly specifying an encoding (unspecified-encoding)
bin/tests/system/checkds/tests-checkds.py:120:13: W1514: Using open without explicitly specifying an encoding (unspecified-encoding)
bin/tests/system/checkds/tests-checkds.py:206:17: W1514: Using open without explicitly specifying an encoding (unspecified-encoding)
************* Module yamlget
bin/tests/system/digdelv/yamlget.py:22:5: W1514: Using open without explicitly specifying an encoding (unspecified-encoding)
************* Module stress_http_quota
bin/tests/system/doth/stress_http_quota.py:131:13: W1514: Using open without explicitly specifying an encoding (unspecified-encoding)
************* Module tests-rpz-passthru-logging
bin/tests/system/rpzextra/tests-rpz-passthru-logging.py:40:9: W1514: Using open without explicitly specifying an encoding (unspecified-encoding)
bin/tests/system/rpzextra/tests-rpz-passthru-logging.py:44:9: W1514: Using open without explicitly specifying an encoding (unspecified-encoding)
The yamlget.py file was changed in !3311 as part of making the
python code pylint and flake8 compliant. This omitted setting
'item' to 'item[key]' which caused the digdelv yaml tests to fail.
Also, the pretty printing is not really necessary, so remove
the "if key not in item; print error" logic.
