Adds simple test Godot program for database access. (This specific to PostgreSQL, but can be adapted.) Sourced from our menu and Luke's provided reference: https://godotengine.org/asset-library/asset/985
Note: before using, update the screens/DBTest_Postgres.gd script for relevant testing user, password, host, port, database values. (Search on comment "TODO." For anything aside from this rudimentary testing we obviously cannot write these values directly in the code.)
Any SQL tests you need to run can be updated in the _executer function code block. Currently it expects a characters database that it just selects all and prints to console for verification testing.
