We test pgadmin in nixosTests, because it needs a running postgresql instance.
This is now unnecessary since we can do so in the package itself.
This reduces the complexity of pgadmin and removes the need for the extra
nixosTests.
Also setting SERVER_MODE in `pkg/pip/setup_pip.py` does not have any effect
on the final package, so we remove it.
In NixOS, we use the module, which expects SERVER_MODE to be true (which it defaults to).
In non-NixOS installations, we will need the directory /var/lib/pgadmin and /var/log/pgadmin
Signed-off-by: Florian Brandes <florian.brandes@posteo.de>
e4488f5efe