Merge pull request #1025 from rjc123/newsites

Update TNA timestamp for hs2
Merge pull request #1026 from rjc123/newsites

Add query strings for Crown Commercial Service
Gracefully abort if arguments missing

I forgot to supply any arguments to tools/sitemap.sh and it started generating
bogus files and errors. I then had to clean that up and read the source to
figure out what to do. Aborting with a usage message is something people
generally expect.
Merge pull request #1027 from alphagov/gracefully_abort_if_arguments_missing

Gracefully abort if arguments missing
Configure hs2 assets subdomain