Initial commit: Telegram monitoring bot with external configuration

- Externalize configuration to YAML (config_example.yaml)
- Add config loader with validation in bot.py
- Implement DatabaseManager for activity logging and user stats
- Add message handlers with topic awareness
- Include setup_venv.sh for automated environment setup
- Add requirements.txt with dependencies (python-telegram-bot, PyYAML)
- Comprehensive README with setup and configuration instructions

setup_venv.sh

@@ -0,0 +1,11 @@
+#!/usr/bin/env bash
+# Kurzes Skript zum Erzeugen und Vorbereiten einer virtuellen Umgebung
+set -euo pipefail
+
+python3 -m venv .venv
+source .venv/bin/activate
+python -m pip install --upgrade pip
+pip install -r requirements.txt
+
+echo "Virtuelle Umgebung eingerichtet und Abhängigkeiten installiert."
+echo "Aktiviere sie mit: source .venv/bin/activate"