* refact: Changes required for gorm v2
* refact: Add db.DB wrapper and refact all test fixtures to use it
Stop leaking the gorm abstraction within our unit tests.
* refact: Migrate direct calls to pq to pgx driver
The refactor will remove the remaining direct dependencies on
the pq driver which has been deprecated in favor of the pgx
driver.
It includes the addition of common.SqlOpen which is a wrapper around
sql.Open, which is needed to deal with the driver name changing from
"postgres" to "pgx" but in our code base the dialect and driver are
synonyms.
This is modeled after the internal/docker package to make it easy to use as a
replacement. Instead of creating a new docker container for each test,
it will create a new database in an existing database container, using a
template database as a source. This assumes that the template database
exists and already has the schema migrations run against it.
The default template is `boundary_template` which should already have
all migrations applied. However, some tests require an empty database to
test the migration code. In these cases the `template1` template
database should be used, ie:
dbtest.StartWithTemplate("postgres", dbtest.WithTemplate("template1"))