Add ntfy push notifications + mailrise SMTP bridge

- ntfy: self-hosted push notification service (port 8086)
- mailrise: SMTP-to-ntfy converter (port 8025)
- Configs in ./ntfy/server.yml and ./ntfy/mailrise.yml
- Token-based authentication for ntfy
- Updated docs and .gitignore

ntfy/mailrise.yml

@@ -0,0 +1,13 @@
+smtp:
+  hostname: mailrise
+  port: 8025
+
+ntfy:
+  default:
+    url: http://ntfy:8086
+    token: tk_yourtokenhere
+
+configs:
+  alerts: alerts
+  backups: backups
+  paperless: paperless

ntfy/server.yml

@@ -0,0 +1,6 @@
+listen-http: ":8086"
+cache-file: "/var/cache/ntfy/cache.db"
+auth-file: "/var/lib/ntfy/auth.db"
+auth-default-access: "deny-all"
+behind-proxy: true
+base-url: "https://ntfy.kansaigaijin.com"