Bump panopticon timeout for publication script

As this script publishes 10000+ documents, do the same here as we had to
do for the import; namely bump the timeout for Panopticon so it doesn't
  timeout.

Further, let's take the opportunity to log a couple of different errors
so we can tell at a glance if an error is to do with API interaction or
another, more non-specific error.
Merge pull request #284 from alphagov/fix-publication-script

Bump panopticon timeout for publication script