Debian 10.8 release process - Yay, it's a lot faster

Thanks to the changes behind the scenes, images are now being produced significantly faster than they were: the embarrassingly parallel speed up has worked, though at slight cost to the predictability of when we get each architecture produced for us to test.

Thanks, as ever, to Sledge, RattusRattus and Isy over in Cambridge and to schweer who painstakingly tests all the debian-edu releases.

83 out of 94 steps done and it's only 13:50 GMT - less popular architectures are coming on apace. There's still a lot of testing to do: we will never be able to test s390x for example. Other architectures - including mips* - we have no machines, we're building as best efforts and we can't guarantee how well they will work for anyone.

Anybody installing the less popular architectures please let us know that you've installed them and how you get on. We'd like to see a positive report as well as bugs: we don't see much feedback at all to know how useful they are: evidence of installs on any architecture is always helpful to us.