backup: reset modules after restore

src/knot/conf/module.c

src/knot/conf/module.h

src/knot/events/handlers/backup.c

src/knot/nameserver/query_module.c

src/knot/nameserver/query_module.h

src/knot/zone/zone.c

src/knot/zone/zone.h

tests-extra/tests/zone/backup/test.py