Drop parallel test databases before running create

If the database isn't dropped in full then tables dropped in a migration
will still exist in the parallel databases.

Because the primary database was being dropped before creation this lead
to intermittent false positives where a test would fail if run against
the primary but would pass if run against one of the parallels where the
table still exists.
Merge pull request #1330 from alphagov/make-jenkins-drop-parallel-db-before-run

Drop parallel test databases before running create
Archived documents count as having been published

These changes ensure that archived editions are included in a
document's change history.
Don't treat archived editions as being in "Preview" state

Previously, only "published" editions were publicly visible on the
site so the logic was fine, but now "archived" editions are also
publicly viewable. This will ensure only pre-public state editions
do not get a change history.
Merge pull request #1333 from alphagov/dont-render-archived-document-change-notes-as-preview

Dont render archived document change notes as preview