doc: packaging: add license block to each .rst.
tests: fix test_list_arches(), there's new architectures listed now.
py3: use sphinx-build-3 (which doesn't encode the minor py version) (RhBug:1098098)

Related: RhBug:1098109
build: 0.4.16-1
deepcopy of sack raises error (RhBug:1059149)