cubicweb #9240765 postgres test database should live in test/data/database [validation pending]

with other test databases. So one can cleanup everything at once

prioritynormal
typebug
done in3.22.0
load0.500
load left0.000
closed by#c9d12d1d3081 [testlib] put postgres test database in test/data/database directory
patch[testlib] put postgres test database in test/data/database directory [applied]