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>

third_party/lieer/default.nix

@@ -1,28 +0,0 @@
-# Lieer is a small tool to synchronise a Gmail account with a local
-# maildir.
-{ pkgs, ... }:
-
-let
-  inherit (pkgs) fetchFromGitHub python3Packages;
-in python3Packages.buildPythonApplication rec {
-  name = "lieer-${version}";
-  version = "1.3";
-
-  src = fetchFromGitHub {
-    owner = "gauteh";
-    repo = "lieer";
-    rev = "v${version}";
-    sha256 = "12sl7d381l1gjaam419xc8gxmsprxf0hgksz1f974qmmijvr02bh";
-  };
-
-  patches = [
-    ./send_scope.patch
-  ];
-
-  propagatedBuildInputs = with python3Packages; [
-    notmuch
-    oauth2client
-    google-api-python-client
-    tqdm
-  ];
-}

third_party/lieer/send_scope.patch

@@ -1,26 +0,0 @@
-From ac7be0f9ad212455d833457bc328ee18eb6a5fdf Mon Sep 17 00:00:00 2001
-From: Vincent Ambo <tazjin@google.com>
-Date: Thu, 10 Dec 2020 11:13:56 +0100
-Subject: [PATCH] remoet: Add 'mail.google.com' OAuth scope
-
-Required for sending emails.
----
- lieer/remote.py | 2 +-
- 1 file changed, 1 insertion(+), 1 deletion(-)
-
-diff --git a/lieer/remote.py b/lieer/remote.py
-index 9f3e871..6f5a71e 100644
---- a/lieer/remote.py
-+++ b/lieer/remote.py
-@@ -26,7 +26,7 @@ from oauth2client.file import Storage
- from pathlib import Path
- 
- class Remote:
--  SCOPES = 'https://www.googleapis.com/auth/gmail.readonly https://www.googleapis.com/auth/gmail.labels https://www.googleapis.com/auth/gmail.modify'
-+  SCOPES = 'https://www.googleapis.com/auth/gmail.readonly https://www.googleapis.com/auth/gmail.labels https://www.googleapis.com/auth/gmail.modify https://mail.google.com/'
-   APPLICATION_NAME   = 'Lieer'
-   CLIENT_SECRET_FILE = None
-   authorized         = False
--- 
-2.29.2.576.ga3fc446d84-goog
-