feat: add Python app package template

- Create Python application Dockerfile template
- Create Python app CloudronManifest.json template
- Create Python app start.sh template
- Include Django and Flask support
- PostgreSQL integration with wait logic
- Django migrations and collectstatic
- Admin user creation support
- Environment variable configuration
- Health check implementation

Template features:
- Python 3-slim base image
- PostgreSQL addon support
- Localstorage addon support
- Database wait and connection logic
- Django-specific support (migrations, collectstatic, admin creation)
- Flask support (simple startup)
- Configurable workers (NUM_WORKERS)
- Port 5000 (configurable)
- Health check endpoint

Environment variables:
- DJANGO_SETTINGS_MODULE: Django settings module
- SECRET_KEY: Django secret key
- ALLOWED_HOSTS: Allowed hosts for Django
- DATABASE_URL: PostgreSQL connection URL (auto-generated)
- ADMIN_USERNAME: Admin username (optional)
- ADMIN_EMAIL: Admin email (optional)
- ADMIN_PASSWORD: Admin password (optional)
- NUM_WORKERS: Gunicorn workers (default: 4)

💘 Generated with Crush

Assisted-by: GLM-4.7 via Crush <crush@charm.land>

Package-Templates/python-app/start.sh.template

@@ -0,0 +1,59 @@
+#!/bin/bash
+
+set -e
+
+# Cloudron PostgreSQL connection
+DB_NAME=${CLOUDRON_POSTGRESQL_DATABASE:-app}
+DB_USER=${CLOUDRON_POSTGRESQL_USERNAME:-app}
+DB_PASSWORD=${CLOUDRON_POSTGRESQL_PASSWORD}
+DB_HOST=${CLOUDRON_POSTGRESQL_HOST:-127.0.0.1}
+DB_PORT=${CLOUDRON_POSTGRESQL_PORT:-5432}
+
+echo "Database host: $DB_HOST"
+echo "Database port: $DB_PORT"
+echo "Database name: $DB_NAME"
+
+# Django configuration
+export DJANGO_SETTINGS_MODULE=${DJANGO_SETTINGS_MODULE:-config.production}
+export SECRET_KEY=${SECRET_KEY:-cloudron-secret-key-change-in-production}
+export ALLOWED_HOSTS=${ALLOWED_HOSTS:-'*'}
+
+# Database URL (for non-Django apps)
+export DATABASE_URL=postgres://${DB_USER}:${DB_PASSWORD}@${DB_HOST}:${DB_PORT}/${DB_NAME}
+
+# Wait for PostgreSQL to be ready
+echo "Waiting for PostgreSQL to be ready..."
+until PGPASSWORD=$DB_PASSWORD psql -h "$DB_HOST" -p "$DB_PORT" -U "$DB_USER" -d "$DB_NAME" -c '\q' 2>/dev/null; do
+  echo "PostgreSQL is unavailable - sleeping"
+  sleep 2
+done
+
+echo "PostgreSQL is ready!"
+
+# Run Django migrations (if Django)
+if [ -f "manage.py" ]; then
+  echo "Running Django migrations..."
+  python manage.py migrate --noinput
+
+  echo "Collecting static files..."
+  python manage.py collectstatic --noinput
+
+  # Create admin user if specified
+  if [ -n "$ADMIN_USERNAME" ] && [ -n "$ADMIN_PASSWORD" ] && [ -n "$ADMIN_EMAIL" ]; then
+    echo "Creating admin user..."
+    echo "from django.contrib.auth import get_user_model; from django.core.management import call_command; User = get_user_model(); User.objects.create_superuser('$ADMIN_USERNAME', '$ADMIN_EMAIL', '$ADMIN_PASSWORD') if not User.objects.filter(email='$ADMIN_EMAIL').exists() else None" | \
+        python manage.py shell 2>/dev/null || echo "Admin user may already exist"
+  fi
+fi
+
+# Start application (modify as needed)
+if [ -f "wsgi.py" ] || [ -f "config/wsgi.py" ]; then
+  echo "Starting Django with gunicorn..."
+  exec gunicorn config.wsgi:application --bind 0.0.0.0:5000 --workers ${NUM_WORKERS:-4}
+elif [ -f "app.py" ]; then
+  echo "Starting Flask application..."
+  exec python app.py
+else
+  echo "No entrypoint found, trying default..."
+  exec "$@"
+fi