refactor(tazjin/emacs): Switch to sending mail via lieer

This drops the msmtp requirement from my configuration; there's still
some cleanup to be done but I need to double-check this in a few
environments first.

Change-Id: I298f4ff77b45cb214fbccee84e9bbd861508d11a
Reviewed-on: https://cl.tvl.fyi/c/depot/+/3132
Tested-by: BuildkiteCI
Reviewed-by: tazjin <mail@tazj.in>

users/tazjin/nixos/frog/default.nix

@@ -1,7 +1,7 @@
 { depot, lib, pkgs, ... }:
 
 config: let
-  inherit (depot.third_party) lieer;
+  inherit (pkgs) lieer;
 
   quasselClient = pkgs.quassel.override {
     client = true;

users/tazjin/nixos/tverskoy/default.nix

@@ -211,7 +211,6 @@ in lib.fix(self: {
     # programs from the depot
     (with depot; [
       screenLock
-      third_party.lieer
       tools.nsfv-setup
       users.tazjin.emacs
     ]) ++
@@ -238,6 +237,7 @@ in lib.fix(self: {
       iftop
       imagemagick
       jq
+      lieer
       manpages
       mosh
       msmtp
@@ -247,8 +247,8 @@ in lib.fix(self: {
       notmuch
       openssh
       openssl
-      pass
       paperlike-go
+      pass
       pavucontrol
       pinentry
       pinentry-emacs