PostgreSQL: Don't specify a default PostgreSQL package

The user should specify which major version to use
(e.g. "services.postgresql.package = pkgs.postgresql92").  We can't
really provide a sensible default, because such a default would have
to be updated from time to time, and there is no automated upgrade
procedure.  So leave upgrading to the user.
xsession: remove duplicate sourcing of /etc/profile
remove redundant if
xsession: add config option to let systemd handle lid/power events
add e17 desktop manager

desktop-manager is a bit misleading in this case as there is no
session yet and most apps are still missing. This can eventually
grow further once more e17 apps get packaged for nix.

However, for now, I need to initialize some e17 dbus services to
have the "terminology" terminal emulator provide gfx previews.
postgresql: version the dataDir by default

Among other things, this will make migrating between versions easier

Signed-off-by: Shea Levy <shea@shealevy.com>
Fix nixos evaluation on systems that haven't set postgresql.package

Signed-off-by: Shea Levy <shea@shealevy.com>
Revert "Fix nixos evaluation on systems that haven't set postgresql.package"

This reverts commit 1e543984bcaf5c9e2c26a1b3de86ffa4d9fe7ba3.

This would have been nice if we had had it from the start, but now it
just breaks things for existing users. Maybe we can add it conditionally
when new postgres versions come out.

Signed-off-by: Shea Levy <shea@shealevy.com>
Revert "postgresql: version the dataDir by default"

This reverts commit 7f1e728606e99dbf394790bdf6eccca685fe981b.

This would have been nice if we had had it from the start, but now it
just breaks things for existing users. Maybe we can add it conditionally
when new postgres versions come out.

Signed-off-by: Shea Levy <shea@shealevy.com>
release-combined: Remove maintainers from everything but `tested'

This will make it possible to turn on email notifications for the
`tested' job without duplicating emails for all the other jobs

Signed-off-by: Shea Levy <shea@shealevy.com>
iso_minimal_new_kernel
add thinkfan service