feat: Add Additional SMTP Headers to Decrease Spam Score (#3031)

* add html2text util

* add various missing email headers

* lint

mealie/services/email/email_senders.py

@@ -3,6 +3,10 @@ import typing
 from abc import ABC, abstractmethod
 from dataclasses import dataclass
 from email import message
+from email.utils import formatdate
+from uuid import uuid4
+
+from html2text import html2text
 
 from mealie.services._base_service import BaseService
 
@@ -36,7 +40,19 @@ class Message:
         msg["Subject"] = self.subject
         msg["From"] = f"{self.mail_from_name} <{self.mail_from_address}>"
         msg["To"] = to
+        msg["Date"] = formatdate(localtime=True)
         msg.add_alternative(self.html, subtype="html")
+        msg.add_alternative(html2text(self.html), subtype="plain")
+
+        try:
+            message_id = f"{uuid4()}@{self.mail_from_address.split('@')[1]}"
+        except IndexError:
+            # this should never happen with a valid email address,
+            # but we let the SMTP server handle it instead of raising it here
+            message_id = f"{uuid4()}@{self.mail_from_address}"
+
+        msg["Message-ID"] = message_id
+        msg["MIME-Version"] = "1.0"
 
         if smtp.ssl:
             with smtplib.SMTP_SSL(smtp.host, smtp.port) as server: