feat: initial implementation of uptodownbot

Telegram bot for downloading media from any site using yt-dlp.
Supports audio/video/both, quality selection, language picker,
container format selection, playlist pagination, progress updates,
per-user quotas, user preferences, download history, cancel at any step,
polling and webhook modes, proxy support, and SQLite persistence.

.env.example

@@ -0,0 +1,13 @@
+BOT_TOKEN=YOUR_TELEGRAM_BOT_TOKEN
+HTTP_PROXY=
+HTTPS_PROXY=
+DB_PATH=data/uptodown.db
+DOWNLOAD_DIR=/tmp/uptodown
+MAX_FILE_SIZE_MB=2000
+COOKIES_FILE=
+TZ=UTC
+BOT_ALLOWED_USERS=
+BOT_WEBHOOK_URL=
+BOT_LISTEN=:8080
+BOT_TLS_CERT=
+BOT_TLS_KEY=