Bug 18448: Fix a few db_dependent tests

Bug 18448: Fix a few db_dependent tests

Tests in db_dependent may expect a Koha database, but should not rely on
hardcoded categories, currencies, branch codes, etc.

This patch fixes a bunch of those. But this is a continuous project. We also
need QA to closely watch new edits.

Accounts.t: hardcoded category PT replaced
Acquisition/OrderFromSubscription.t: hardcoded USD
Acquisition/StandingOrders.t: same
ArticleRequests.t: create itemtype, branch and category for testing
AuthorisedValues.t: remove $dbh, add two test branches
AuthoritiesMarc.t: add hardcoded GEOGR_NAME authtype
Bookseller.t: add test currency
Koha.t: add test itemtype instead of hardcoded BK
UsageStats.t: add test branch and category

Test plan:
Run the adjusted tests.

Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
All tests successful (see comment #9)
Signed-off-by: Marc Véron <veron@veron.ch>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>