conf: enable identity/version/nsid by default

doc/reference.rst

man/knot.conf.5.in

src/knot/nameserver/chaos.c

src/knot/nameserver/process_query.c

src/utils/knot1to2/cf-parse.tab.c

src/utils/knot1to2/cf-parse.y

tests-extra/tests/chaos/ident/test.py

tests-extra/tests/chaos/version/test.py

tests-extra/tests/edns/nsid/test.py

tests-extra/tools/dnstest/server.py