Azure: Rework world build to directly use the container

Azure: Rework world build to directly use the container

While we had problems historically using buildman inside of a container
when invoked directly via Azure, rather than calling docker in our
script, that is no longer the case. We can make the job a bit easier to
understand by running it more normally. The challenge here is that our
container normally runs with an unprivileged user that we have populated
tools for and Azure creates and uses a new unprivileged user. Copy what
we need over to the new user.

Signed-off-by: Tom Rini <trini@konsulko.com>