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.

.gitignore

@@ -0,0 +1,9 @@
+.build/
+*.exe
+*.db
+*.db-wal
+*.db-shm
+.env
+.DS_Store
+tmp/
+