Rename tests/ to tests-extra/ to make space for C TAP Harness tests

tests-extra/Makefile

tests-extra/chkjournal.c

tests-extra/functional/.gitignore

tests-extra/functional/README

tests-extra/functional/functests.py

tests-extra/functional/tests/axfr/bind_knot/test.py

tests-extra/functional/tests/axfr/interrupt/test.py

tests-extra/functional/tests/axfr/knot_bind/test.py

tests-extra/functional/tests/axfr/knot_knot/test.py

tests-extra/functional/tests/basic/flags/test.py

tests-extra/functional/tests/basic/rcode/test.py

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

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

tests-extra/functional/tests/ddns/forward/test.py

tests-extra/functional/tests/ddns/prereq/data/ddns.zone

tests-extra/functional/tests/ddns/prereq/test.py

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

tests-extra/functional/tests/edns/payload/test.py

...xtra/functional/tests/records/obsolete/data/obsolete.zone

tests-extra/functional/tests/records/obsolete/test.py