feat: initialize newsletter project with IMAP email processing and Discord integration

- Add Cargo.toml for project dependencies
- Create Dockerfile for building and running the application
- Add docker-compose configuration for service management
- Implement email monitoring and processing in main.rs
- Parse emails and send notifications to Discord
- Include configuration file for IMAP and Discord settings

compose.yml

@@ -0,0 +1,9 @@
+services:
+  memos-rss:
+    image: ghcr.io/imnyang/newsletter:latest
+    restart: always
+    env_file:
+      - .env
+    volumes:
+      - ./config.toml:/usr/app/config.toml
+      - /etc/localtime:/etc/localtime:ro