Since swh.core 0.3.0, the database creation (superuser) and database
initialization (user) operations have been split for databases managed using raw
SQL.

• Override the postgresql containers for these services to avoid creating an

empty database.

• Add an entry for the template1 database to .pgpass so other containers can

connect to it

• extend wait_pgsql to take a database name as first argument

cleaned up all containers, rebuilt swh/stack and ran tox in the
docker directory, to successful completion.